The most asked Q for a new or a regular user - Fedora Core 2-9 with KDE. Uncover the Secrets.

Release 11.1 for Fedora Core 2 - Fedora 9, using for RH9

Release 11.1 at 2009 December 12th for Fedora Core 2 - Fedora 9. Using for RH9

To help a new/regular user getting her/his job done in an easy/quick/effective and productive way, I decided to write this FAQ. The FAQ is a collection of my ideas and experiences, as well as tips from books and the internet/newsgroups. It weights mostly towards all the "trivial" questions that a new user would ask. The further you go down the FAQ the more advanced the questions will become. The nearby bottom part is for X Window, and the bottom part is for new hints. For helping you to get around the jungle, please use the Key index, use it together with the find-function in your browser.

This FAQ will NOT do all the work for you. It neither helps you to install a TV-card (I do it anyway :-)), burn a CD nor solve diverse problems on some specific Linux applications. But it will give you some ideas as to how you can solve the problem. All the places where I wrote <filename> means that you just write the filename without the <>. Be aware that some of the commands require the root password and some of them need to be installed from either Redhat's CD1, CD2, CD3, CD4 or from the or RPMSeek or from the RPMfind. It will take a short time to remember all the commands and understand the scripts, just keep practice (for the long & winding script split it to a new line each time there is a semicolon for easy reading).

This "Uncover the Secrets" is dedicated specially to my supporting and dear parents, I owe them everything... With no doubt, I owe the inspirations to Richard Stallman, Linus Torvalds, the LINUX/GNU developers/maintainers, the HOWTO project, the Newsgroup linux.redhat and not least the publications from SSLUG Denmark.

Enjoy...I hope it saves you some time and I hope you use some of the surplus time to develop something even better.

0. What should I do first to get the most benefit for my Linux-effort?Read carefully the useful "RELEASE-NOTES", the "Installation Guide" and the "Getting Started Guide" from Redhat boxed set or read them from Redhat Manuals
1. Which Linux distribution is most popular?
2. Top 500 super computer in 2009
3. How many mount points do I need for a Linux installation, and what about multiple boot?Clicking here
4. Any good file manager a la Norton Commander? (you can't do anything if you don't know what you have)Yes, use Midnight Commander (mc-4.5.x.i386.rpm) OR krusader (X-application a la Total Commander). Type: mc in a console. Use F3/F4 as a text editor in Midnight Commander.
5. How to start X Window from console?startx
6. How to use copy and paste?To copy a text just marking it (no clicking), to paste it just clicking on the right button (in X Window you need to click both buttons or a third button; reconfigure your mouse with the mouseconfig command)
7. Howto shutdown my linux?init 0 ; Use init 6 or CTRL+ALT+DEL for reboot ; shutdown +5 "Achtung, achtung the server is going on strike in 5 minutes sharp. The strike will be over in about 20 minutes"
8. Howto use a command?man (man=manual, try: man ls; man mount) OR in X Window: Alt+F2 and type #ls
9. Which commands do they have in Linux?info; pinfo; ls /bin; ls /usr/bin; mc /usr/sbin ; mc /usr/X11R6/bin (for X Window) ; xman (X Window)
10. Howto list ALL the Linux commands I am allowed to use?Press <Esc> and then press *
11. Are you realized that there is file completion in Linux?Type one or two letter of a command and then press <TAB> twice
12. Which commands should I learn in the beginning?You can almost get everything with your mouse in X just like in Windows. If you like the challenge I suggest that you try: ls, locate (find), grep, rpm and vi.
13. I know a good command in Windows, do they have it in Linux?apropos XXX | more ;where XXX is the good command (build the database with /usr/sbin/makewhatis for the first time)
14. What is the system hardware info (machine info) of my PC?dmidecode
15. Are there any Linux monthly magazine?,,,
16. What is a good and fast text editor?Use F3 or F4 in mc (mcedit) or kedit
17. Now I can shutdown a Linux server, it is the time, I wannabe a GURU.To become a Guru and do not forget to buy some Linux books when you go shopping :-).
18. How to give an user the privilege to use the root commands? (just like mount, shutdown etc)man sudo
19. Where are the documentations about the Linux system?khelpcenter (X Window) and Documentations from
20. Where are the most technical documentations about a Linux/PC system?ls -l /usr/src/`uname -r`/Documentation
21. Howto understand the start-up init scripts at /etc/rc3.d ? (a la autoexec.bat)more /usr/share/doc/initscripts-7.XX/sysvinitfiles
22. Howto understand the settings of the global system and the network in /etc/system?less /usr/share/doc/initscripts-7.XX/sysconfig.txt
23. Which applications/programmes do I have on my PC?system-config-packages OR rpm -qa |more OR more /var/log/rpmpkgs (q means query; a=all; f=file; l=list))
24. Howto install a new application?system-config-packages OR using the powerfull rpm (many times better than TRU64 setld, Solaris pkg*, AIX lslpp) try: rpm -ivh <the RPM file> (to update use the option -U: rpm -Uvh)
25. What packages do I install lately?rpm -qa --qf "%{INSTALLTIME:date} %{NAME}\n"
26. Is it a table of contents (a list) of all the RPMs in the RPM directory on the CD?look at the text file TRANS.TBL at the RPMS directory
27. Howto uninstall the application doom?1)Find the package name: rpm -qa| grep doom 2)Uninstall with: rpm -e <name of the package from step 1>
28. Do I have the webserver apache application?rpm -qa | grep http (q means query, so "qa" means "query all")
29. Howto find from which package a file is from?rpm -qf </path/filename> (q means query, so "qf" means "query files")
30. Howto list files in a RPM file?Use mc OR rpm -qpl XXX.rpm OR rpm2cpio XXX.rpm |cpio -t
31. I wonder where are all the files belong to a package, say apache?1)Find the package name: rpm -qa| grep apache 2)Show the files: rpm -ql <name of the package> (do a " |grep conf" to get the configuration file)
32. I interest in sound/music, how to find any thing about it?apropos sound | more ;(build the database with /usr/sbin/makewhatis for the first time)
33. A good sound editor for analysing and recording the audio audacity
34. Where can I find a MP3 player?amarok, mplayer, vlc, smplayer, rhythmbox, xmms (get it from the internet)
35. Howto rip and encode CD audio to mp3 (or ogg format; needs grip*.rpm)?grip (needs the lame package) OR ffmpeg -i file.wav -ar 44100 -ab 128 outfile.mp3 ; (using mpg123 to convert the mp3 format to wav (mpg123 --wav file.wav file.mp3)
36. How to convert a wma format to mp3? (needs mplayer and lame)mplayer -vo null -vc dummy -af resample=44100 -ao pcm <wma file> && lame -m j -h --vbr-new -b 160 audiodump.wav -o output.mp3
37. Howto grab the audio from a wmv/flv video file and convert it to mp3?ffmpeg -acodec mp3 -ab 128 -ar 44100 -i /mnt/cdrom/XX.wmv XX.mp3 OR ffmpeg -i YY.flv -vn -acodec copy YY.mp3
38. Howto convert a flv video to mpg (and the other way around)? (audio bitrate=56kbit/s; audio samplerate=22050Hz; bitrate=500kb/s)ffmpeg -i XXX.flv -ab 56 -ar 22050 -b 500 -s 320240 XXX.mpg OR ffmpeg -i ZZ.mpg -ar 22050 -acodec libmp3lame -ab 32k -r 25 -s 320x240 -vcodec flv ZZ.flv
39. Howto convert flac to mp3?flac -d *.flac and then lame *.wav
40. Is there a chat client a la messengergaim (V0.74) supports protocol AIM/ICQ, Yahoo, MSN, IRC, Jabber (support Groupchat), Napster; micq; Using Gnomemeeting for video conference
41. How to write a message (chat) to my collegue at the other building?talk, write (using "w" to getting the tty)
42. How to chat by using netcat?nc -vl 8999 ; and the the other user type "nc <your hostname> 8999"
43. Howto get a DVD/VCD player?mplayer (mplayer dvd://1 -chapter 4 -ss 22 -flip ; OR from a local harddisk, mplayer dvd:// -dvd-device /home/<my-home-dir> -chapter 12 ; works great, supports many formats; read the FAQ and the divx4 section)
44. What is my kernel version?uname -r OR procinfo (procinfo is from procinfo*.rpm)
45. What is my Redhat version?cat /etc/redhat-release
46. Howto list hidden files?ls -a (all hidden files start with a dot in Linux)
47. How to get a file's property?stat <file> (stat*.rpm)
48. Why can I not delete my file? (maybe because of the "not-delete" attribute setting in your file by the command chattr)chattr -i -V <your file>
49. The PC boots so fast, I could not catch all messages.dmesg OR redhat-logviewer OR more /var/log/messages
50. How to colorize my log file? (needs logcoloriser-XXX.rpm) /var/log/messages|more OR loco /var/log/messages
51. How can I get a console windows?xconsole (test it with: "echo ocean >/dev/console")
52. Howto change foreground/background colour/color of my console?setterm -term linux -foreground blue; setterm -term linux -background magenta
53. Where do the Linux peoples hide all the log files?system-logviewer OR cd /var/log (web-, ftp-, samba-, mail-, ssh-log etc)
54. What are running right now?ps -ax
55. What is my process status?procinfo (procinfo is from procinfo*.rpm)
56. Howto pause a process?kill -STOP ; kill -CONT
57. Which interrupts, I/O ports are unoccupied?lsdev OR procinfo OR cat /proc/interrupts (lsdev is from procinfo*.rpm)
58. Which hardware devices does the OS (Operative system) recognize?dmidecode; more /etc/sysconfig/hwconf ; lspci ; lspnp ; lsusb
59. How does the OS installs a new hardware device?kudzu (kudzu runs at startup) , it saves infos in /etc/sysconfig/hwconf
60. I want to change my keyboard layout.system-config-keyboard (X Window)
61. Howto install/change a mouse?system-config-mouse
62. What is my PC hardware specifications?cat /proc/cpuinfo AND hwbrowser
63. Howmany RAM/memory do I have?free -k ; more /proc/meminfo
64. Howto find which architecture my kernel configuration is using? (use it when you want to find the right kernel config file)rpm -q --qf '%{ARCH}\n' `rpm -qa|grep kernel-2`
65. What is the time for last boot ?(howlong I had been working?)uptime
66. A quick way to check the connection between the PC and the modem (look at the TxD/RxD leds)cat /bin/sync > /dev/modem
67. What is my enviroment?env ; set
68. What shell do I use?set | grep SHELL
69. Howto see all my last commands? (like F7 in DOS)history or the up/down keys
70. Howto clear the history?history -c
71. How to find the most used commands?history|awk '{print $2}'|sort|uniq -c|sort
72. Does Linux have a calendar?cal 9999 OR gcal -K 1-3 2004 ; try: cal 9 1752 (what is wrong?)
73. Howto find which week we are in?date +%W OR gcal -K
74. Howmuch diskspace (in Kbytes) do I have?df -k
75. Howmuch diskspace does the directory /home occupy? (rounded up to the number of blocks)du -ks /home OR du -chx --max-depth=1 /home
76. Howmany files am I allowed to write on a partition?df -i (one file/directory uses one inode)
77. How to change the user right/permission on a file/directory?man chmod; man chown; man chgrp
78. Howto mount/use a CDROM? (you need to mount the device at a directory, e.g. /mnt/cdrom) mount -t iso9660 /dev/cdrom /mnt/cdrom ; (if you get any error, try the next hint and look at the softlink (man ln) of /dev/cdrom)
79. I got the error message when mounting a cdrom "/dev/cdrom is not a valid block device", what should I do?depmod -a
80. I cound not unmount/reject my CDROM with "umount /dev/cdrom", I got the error "Device is busy"fuser -muv /dev/cdrom ;it shows you who "locks" the device, ask/kill then that user/process to go away from the CDROM mountpoint before retry umount.
81. Howto mount an iso file? (a la isobuster)mount -t iso9660 file.iso -o ro,loop /mnt
82. Howto mount a floppy?Click the FLOPPY icon on the desktop OR type "mount /dev/fd0 /mnt"
83. Howto format a floppy with a king-format?fdformat /dev/fd0u1680 (or fd0u1760 etc)
84. Howto mount a dos partition?mount -t vfat /dev/hda1 /dos/dosc (make new directory with: mkdir /dos/dosc)
85. Which partitions are mounted?mount
86. Howto mount my disk automatically at boot?cat /etc/fstab ; man fstab
87. Howto make a bootdisk?mkbootdisk `uname -r`
88. I am tired of mounting my CDROM, howto avoid it? (using it by enter: cd /auto/cdrom; unmount it by waiting 60s or using umount /auto/cdrom)Click the CDROM icon on the desktop OR Add "/auto /etc/auto.misc --timeout=60" in /etc/auto.master (without quotas); add "cdrom -fstype=auto :/dev/cdrom" in /etc/auto.misc; service autofs restart
89. Howmany partitions do I have?fdisk -l OR sfdisk -l
90. I want to have more informations of my hard drivehdparm -i /dev/hda
91. Howfast is my brand-new hard drive?hdparm -t /dev/hdX ; where X is the device for your new hard drive
92. Howto install a sound card?system-config-soundcard (sometimes the "suggested" driver does not work either (especially the module snd-via82xx for the onboard sound chip VT8233 AC97), you need to wait for another driver or buy a cheap SoundBlaster card)
93. Is there a Sound Studio to record my old tapes? (via line-in from my SoundBlaster)record OR sox OR SoundStudio-1.0.3-5.i386.rpm
94. I get problem with my sound after a kernel (..etc..) upgrade, what shoul I do?You can always try to get the newest alsa-xx (Advanced linux Sound Architecture) package from the net. 1)run kcontrol, enable the sound system at the "Sound & Multimedia" 2) at the hardware-tab, choose "Advanced..", click ok 3) run "alsaconf", just accept all the questions (no sound yet) 4) play a mp3 in 5) run "alsamixer", using the arrow to go to the right and press M (mute) at the IEC958C (or just press M on all buttons until the sound is on) 6) press Esc to exit 7)to save the setting, you must use "kmix", click "advanced" at the Output-tab, the light at "IEC958 Capture Monitor" must be off 8) press "Ctrl+M", at the Settings menu, choose "Conf Kmix" and then flag all the four settings 9) click OK 10) DONE (NB: you do not need to run step 5 & 6 if you run step 7, but I want to show you the opportunities inside the text based alsaconf)
95. Howto easily install an internet connection with a modem?Clicking here
96. How to install a printer?printconf-tui ; printconf-gui (in X Window)
97. I have so many problems with my lpc ; man lpinfo and visit linuxprinting
98. How to install a network card?Clicking here
99. Howto set my NIC to full duplex? (required a new NIC with MII interface)mii-tool -F 100baseTx-FD eth0 (try ethtool too)
100. Howto install a Hauppauge PVR150MCE TV-tuner?Clicking here
101. Howto change a hostname?Do it on /etc/sysconfig/network and /etc/hosts; reboot (not enough with restarting of the network)
102. How to assign a dhcp client a fix hostname?Add DHCP_HOSTNAME=<a name you want> in /etc/sysconfig/network-scripts/ifcfg-eth0 ; service network restart
103. What is the ethercode (the uniq HW address of a networking interface; "ifconfig") for the networking manufacturer D-Link?grep -i D-Link /var/arpwatch/ethercodes.dat (try "grep 0:50:4 /var/arpwatch/ethercodes.dat")
104. Howto install DNS?bindconf (bad, I prefer vi :-) )
105. Where is the configuration files for DNS?/etc/named.conf and /var/named and resolv.conf
106. Does the kernel support USB2?lspci; lsusb ; hwbrowser
107. How can I use/mount a USB memory stick? (Linux emulates it as a scsi device)Run "kudzu" and then execute: mount -t auto /dev/sda /mnt/usb-memstick (try sdb or sdc if you already have a SCSI device on the system)
108. Does the kernel support NTFS?more /proc/filesystems (in this file you can see which FS the kernel supports) OR by using the driver directly "ntfsprogs" (list the /tmp on the NTFS partition hd5 and unpack a mp3 file: ntfsls -p "/temp" -d /dev/hda5; ntfscat /dev/hda5 "/temp/song1.mp3" >song1.mp3)
109. Howto build a module to support the NTFS filesystem?Build NTFS from Jim Hayward
110. Howto adjust the system clock?date -s HHMM and then hwclock -w to update the CMOS/hardware clock
111. Howto adjust my clock with a reference/atomic clock?ntpdate (remember to run "hwclock -w" to passe the setting to the CMOS clock)
112. My PC is slow, why?gnome-system-monitor ; top ; ps -ax (try to find which processes eat your CPU clock) ; free, iostat, ll (check the RAM/swap)
113. Howto measure the total running time of a command?time <command>
114. How much memory does my application used?memusage <your application>; memprof
115. Why is my hard drive keep running in the background?Move the jobs at /etc/crond.* to an another place (especially slocate.cron)
116. What more can I do to improve the system performance?On a non-production PC disabling all the following services (chkconfig XXX off): kudzu, sendmail, crond, anacron, apmd, pcmcia, nfs
117. What is the real size of my huge /var/log/wtmp?ls -s /var/log/wtmp
118. What is TOP25 of the most CPU-eating on my PC?clear;top -b -S|head -25
119. Can I work without the command top?Of course you can, "needs get peoples to spindle". Use: ps aux|sort -nk3 (sortering the CPU util column)
120. Howto list all the parents and children of a process?ps -A --forest OR pstree -p XXX (pstree from psmisc-20.*.rpm)
121. What is the name of the program I had just started from the KDE Windows menu?ps -Af --sort start_time
122. Howlong does it take for a Linux installation/upgrade and howlong does it take to start KDE with startx, Konqueror and Mozilla?On a 2GhzAMD/512MB : about 50 minutes (with many applications). Bad media, old CD-driver and old hard driver will extend the installation time essentially); 25 seconds to start KDE, 3s to start Konqueror, 5s for OpenOffice Write and 5s for Mozilla. Take a look at /var/log/messages if it takes long time.
123. Where is the autoexec.bat?/etc/rc*.d ; use khelpcenter (the lifebelt icon) to learn more about this subject.
124. What services/daemons start at system reboot?chkconfig --list OR ls /etc/rc.d/rc3.d/S* OR ls /etc/rc.d/rc5.d/S* if you use X-login
125. Howto restart a service?service <name of the service> restart ; replace restart with stop if you want to stop a service
126. I want to record all my actions into a text file and send it to a developer.script report.txt ; break with CTRL+D
127. Howto directs output on the screen to a log file?use >& ; for example startx >& x.log will log all the output from startx into a file called x.log
128. Howto print the lines between 10 and 55?sed -n '10,55p' <your_file>
129. Howto join each three lines in a file together? sed '$!N;s/\n/ /g;$!N;s/\n/ /g' <my file>
130. How to remove those >> character from a text file?sed -e 's/\(^>\s*\)\(\w.*\)/\2/;s/\(^>\s*\)\(\W.*\)/\2/' <myfile> |tr -d '>'
131. Howto print only those lines containing the character XX and YY?sed -n '/XX/p; /YY/p' <my file>
132. A list of the regular expressions (using in perl, sed, egrep etc)
133. Who are on the system at the moment?who ; w
134. Who am i?whoami
135. Who are you?finger <user account>
136. What is my IP-address and MAC-address for my network card?ifconfig
137. What is LISA (Lan Information Server) ? (a new generation of TNG? :-) )A petit app for monitoring a network by using ping. Conf /etc/lisarc (read /usr/share/apps/lisa/README); run: lisa; open konqueror and type "lan:/" (without apostrophe)
138. Which files control the network (with DNS)?/etc/hosts, /etc/host.conf, /etc/resolv.conf and /etc/sysconfig/network-scripts/ifcfg-eth0
139. I do not have a network card, I get some warning with the hostname in sendmail and something with a strange host name.Make sure that there is a line " localhost.localdomain localhost machine-name <the strange hostname>" (without quotes) in that file. Please read "man hosts".
140. Does the OS install my PCI soundcard/netcard (eth0) module?lsmod
141. Where is the module configuration file (for loading a driver for a device on the fly)?/etc/modprobe.conf (man modprobe.conf)
142. Where can I find all the HW drivers (as module), which Redhat supports? Use modprobe or insmod to load -l /lib/modules/`uname -r`/kernel/drivers
143. Now I have mounted partition C. I want to use the old-Dos-fashioned notation way, just like c: in stead of cd /dos/dosc. alias c:='cd /dos/dosc' (for permanent solution: write the same in the end of the file ~/.bashrc)
144. Howto save a long command string?Use alias; see the trick above
145. Howto reverse the priority of an alias and a command?Use \ in front of the command, try \vi, \rm
146. Please show me some of the useful aliases. (so if I type: "r net" , I get all the packages with the word "net" inside. net is corresponded to $1, it means the first argument after the command r ; s xinetd restart means restart service xinetd)alias h='history' ; alias c:='cd /dos/dosc'; alias cd='pushd $1' ; alias cdrom='mount /dev/cdrom /mnt/cdrom1'; alias g='grep -lis $1 $2' ; alias log='tail -f /var/log/messages'; alias r='rpm -qa|grep $1'; alias rl='rpm -ql $1'; alias rc='cd /etc/rc.d/init.d' ; alias RPM='cd /mnt/cdrom1/RedHat/RPMS' ; alias s='service $1 $2'
147. Howto split a big file to diskettes? (get my_split<PREFIX>)split -b 1400000 <filename> my_split (collect them with "cat <my_splita> <my_splitb> > <filename>"
148. My younger sister deletes my joystick devices in /dev, howto recreate them?/dev/MAKEDEV js ; man MAKEDEV
149. How can I set up a telnet service? (a threat for security, use ssh instead)Update disable=no in /etc/xinetd.d/telnet (or just enter: chkconfig telnet on); restart the service inetd with: "service xinetd restart"
150. How can I secure my ftp connection?man vsftpd.conf
151. Howto set the timeout for a ftp connection? vsftpd: using data_connection_timeout ; wu-ftpd: At the server_args line in /etc/xinetd.d/wu-ftpd add "-t 1800" (for 30min), restart xinetd with "service xinetd restart"
152. Want to remote control my linux just like with Norton Anywhere in Windows.telnet or ssh or vnc or using a X emulator
153. Is there a good ftp programme a la cute-ftp?gftp (X Window)
154. Does my webserver running?ps -ax | grep httpd
155. How can I restart a webserver?service httpd restart (start/stop/status)
156. Howto disable the httpd service?chkconfig httpd off OR chkconfig --del httpd
157. Howto show which services start at which runlevel?chkconfig --list ; ntsysv (X Window)
158. I want to take a quick look on my web activity.tail -f /var/log/httpd/access_log
159. I want to have an another console window.<CTRL+ALT+F2> <CTRL+ALT+F3> <CTRL+ALT+F4> , etc
160. Somehow , my console becomes invisible, I can not see what I type.reset OR stty sane OR hit <CTRL+V> <CTRL+O>
161. I do not want to echo the key I type on the screenstty -echo ; turn back with "stty echo"
162. Turn off the PC-speaker (the bell)setterm -blength 0 (from window try "xset b off")
163. Where are all the lib files?cd /usr and write: find . -name \*lib\* ; Or use Midnight Commander mc, press ALT+?
164. Howto quickly locate a file?locate <file name> ; NB: updatedb (/etc/crond*) must run everyday to update the database
165. By accident I delete some of the lib (.so) files, I do not know which RPM package it comes from. What should I do?rpmfind or rpm -qf </XXX/lib file> where XXX is the path of the file
166. Which protocols does service pop3 use?more /etc/services | grep pop3
167. Which port does http use?more /etc/services | grep http
168. Howto setup/disable screensaver for a console?setterm -blank (add it at the second line in ~/.bashrc for permanent solution)
169. Howto turn on the NumLock on the console tty1 at boot?Add "setleds +num > /dev/tty1" (without quotas) at the second line in ~/.bashrc for permanent solution
170. Howto change the prompt on my console (the second is with colour)?export PS1=$'[\\u@\\h \\@ :-)]\\$ ' OR PS1='\[\e[1;31m\][\u@\h \W]\$\[\e[0m\] ' OR (PS1="root@`uname -n` # ";export PS1) OR PS1="PRESS_ENTER $(/usr/bin/whoami)@$(/usr/bin/hostname) [\$PWD] PRESS_ENTER# " ; man bash; (add it at the second line in ~/.bashrc for permanent solution)
171. Howto get the key bindings (get a function by pressing a combination of keys) in bash?bind -p
172. Howto timeout an idle connection?Add "export TMOUT=1800" in /etc/profile (in seconds, only for bash and ksh)
173. Howto made a copy of my typing in a buffer in bash shell?Start: press <Ctrl+x> and then hit ( ; typing ; Stop: <Ctrl+x> and then ) ; Get the buffer: <Ctrl+x> and then e
174. Howto use a virtual mouse? (use it if your mouse's movement is choppy; only for X Window)Press <Ctrl+Shift+NumLock> to activate it, press it again to deactivate. Use the keypad to move the mouse. /5=left button; *5=middle; -5=right; 0=keep pressing; .=release
175. Howto convert lowcase letters to uppercase letters at the command line in bash shell?Go to the beginning of a word and press <Alt+u> (for lowcase press <Alt+l>
176. Howto convert from decimal to hex? (16^3 16^2 16^1 16^0 ; 0xF2A=(10*16^0) + (2*16^1) + (15*16^2) = 3882 ; A=10, B=11 ...F=15)echo "obase=16; XXX "|bc ; where XXX is the decimal number
177. Howto convert from hex to decimal?echo "ibase=16; XXX"|bc ; where XXX is the hexadecimal in UPPER case
178. Howto convert decimal to binary? (2^7 2^6 2^5 2^4 2^3 2^2 2^1 2^0 ; 110=(0*2^0) + (1*2^1) + (1*2^2) =7 )echo "obase=2; XXX "|bc ; where XXX is the decimal (use ibase=2 to go the other way)
179. Howto convert decimal to octav? (..8^3 8^2 8^1 8^0 ; 567octav= (7*8^0) + (6*8^1)+ (5*8^2) = 375 ; In octav the number serie is from 0 to 7)echo "obase=8; XXX "|bc ; where XXX is the decimal (use ibase=8 to go the other way)
180. I want to convert decimal number to hexadecimal, octal and binaryperl -lpe '$n=$_;printf "%d %#x %#o %#b\n", $n, $n, $n, $n'
181. How to using floating point in korn/bash scripts?not possible in shell script, but you can use \"bc\": echo \"scale3; 3/4\" |bc -l
182. Howto install a perl modul?cd to the fold, you have the modul, type: perl; make; make test; make install
183. Howto quickly convert a text to hex code?echo abcABC123|xxd
184. How to find the prime number/factors of an integer?factor 13 ; factor 9999999999999999999 (19 times!!! surprised??)
185. How to pack a whole directory?tar czfv output.tar.gz <your dir>
186. How to unpack a tar-gzip file to the directory /opt?tar xzfv your-file.tar.gz -C /opt OR Gnozip ; use tar xvjf file.bz2 -C /opt (for bzip)
187. Howto read a postscript file?gv <> OR ps2pdf <> <output.pdf> OR ghostscript -g800x600 -r100 <>
188. Howto print a text file to a postscript printer?a2ps -P<printer queue> -r --font-size=8 --columns=2 --highlight-level none --print-anyway yes <your_file> OR using (enscript -d<printer queue> -2 -r -f Times-Roman9 -G -j -uSecret <your text file>)
189. How to easily create a postscript file from a text file?enscript -2 -r -f Times-Roman9 -G -j -uSecret <your_file> (check it with "gv <your_file>" ; if you want to print it instead, just change "-pmy_PS" to "-d<printer queue> )
190. Howto convert my man/text page (groff format) to html format?cat <groff file> | man2html >& output.html
191. I get some MAN pages which do not reside at the default MAN-path, how can I open them?Add a new MANPATH variable at /etc/man.config
192. Howto get a plain text version of a man page, without any control codes?man bash | col -b > man-bash.txt
193. Howto schedule an application/a job?man crontab (crontab -e ; you need to know about vi);
194. Howto schedule a job/script to run every 3 hour?add "* */3 * * * <your script>" in your crontab (crontab -e)
195. How to logrotate my log files?put it in crontab: logrotate -f (see "man logrotate", it shows you how to create your own conf file)
196. Please show me some of the "often used" character sequences in vi/less/vim. (Hit Esc before enter the character sequence)1G=home; G=End; 50%=half file ; /=search forward; ?=search backward; n=search again ; 0=begin of line; $=end of line ; word forward/backward=w/b ; quit=q! ; 25<SPACE>=jump 25 positions forward on a line ; y2w=copy 2 words; :\ = seach for a word; :1,4right= right aligning from line 1 to 4; :set nu= numbering lines ; for more execute "vimtutor"
197. Howto turn off the "syntax highlighting" in vim?create a file called ~/.vimrc and insert "syntax off" (without quotas) inside it
198. Howto get a file manager without having Midnight Commander or Konqueror?Just "vi" the directory; try: vi ~ (~ means your home directory)
199. Howto monitor the sensors on my motherboard? (the CPU temperature, the fan RPM; needed lm_sensors-2.8.7-2)ipmitool (Intelligent Platform Management face); run the commando "sensors-detect" and at the end load the suggested modules by hand (modprobe and lsmod). If the application supports your board then "sensors" will output the info from your board. XMBmon can be an alternative
200. Howto test the memory?memtest86
201. Howto convert a DVD to an AVI (with divx codec)? (needs mencoder-1.0-0.16.pre7.1)mencoder (very fast and easy to use, its "man" deserves a 10+. mencoder dvd://1 -chapter 18 -ss 30 -endpos 200 -o mydivx.avi -ovc lavc -lavcopts vcodec=msmpeg4:vbitrate=1200 -ofps 25 -oac mp3lame (or -oac lavc); it encodes chapter 18 for 200s, 30s from the beginning of the chapter; "mencoder -ovc help"shows the supported codecs)
202. Howto easily protect a love letter?vim -x <your letter> ; it then asks for a password
203. Howto spell-check a text file?aspell check -b <your file> (can not handle a html so well, in this case copy a html file to a file WITHOUT extension (f.eks my-file) and then do a aspell)
204. Which jobs are scheduled for the future? ls /etc/cron.* ; crontab -l; awk 'BEGIN{FS=":"};{print $1}' /etc/passwd|xargs -i crontab -l -u {} |more
205. How to control the time for my cron.daily, cron.week?more /etc/anacrontab
206. Unfold a long line to 80 charsfold -w80 <file>
207. I want to compare two files (or directories)diff <file1> <file2> OR vimdiff OR meld OR xxdiff
208. Howto save a path so I could easily return to it?Use pushd in stead of cd ; pushd /etc ; dirs ; pushd
209. Howto find all my old files with the text "Odense"grep -lis -r -I odense .[!.]* ..?* * (thanks to Paul Jarc from; .[!.]* means NO ..)
210. The company gets a new mail address, howto update it in one shot on all the scripts/text? (you need perl: perl-5.6.0-17.i386.rpm)grep -sil "" *| xargs perl -i.old -pe 's/abc\\'; change from to
211. What is the most used commands in Linux?Scott: ls, man, apropos, df, find, grep, top, more, vi, history, mkdir, which, env, ps, cp, rm, lpr, tar, emacs, ping, ftp, telnet, tail, rpm, lsmod, chmod, pwd, nslookup, mail, echo, wc, awk, passwd, perl and of course startx. Admin: find, grep, ps, vmstat, lsof, netstat, traceroute, last, du, mount, fuser, top, iostat, strace, string, make, vi, kill, service, sed, md5sum, tcpdump, snort. System Developer: as, gcc, make, gdb, time, ddd
212. What is the ascii for a character? (you need perl: perl-5.6.0-17.i386.rpm)perl -lpe 'print ord()'
213. The ASCII code.perl -e 'foreach $n (1..255){print $n ." ".chr($n)."\t"}'
214. The alphabet.clear;perl -e 'foreach $n (65..90){print chr($n)." "};printf "\n\n\n"'
215. I have some special production files (starting with prodXXX; where XXX is the number). How can I find the total size of them?ls -l prod* | awk '{s=s+$5};END{print s}' ; (for clarity you can delete END)
216. How can I add a new path to my global enviroment?At the second line in /etc/profile add: PATH=<your new path>:$PATH ; e.g. PATH=/opt/chess/bin:$PATH
217. Howto add a new users? (get a new user abc with uid=600 and gid=600 ; Use 601, 602, 603 ... for a next user. If possible keep them in the same group)groupadd -g 600 sales (do it ONLY once) ; useradd -u600 -g600 abc ; passwd abc
218. Howto lock/block/quarantine a user?passwd -l <user account> (release it with passwd -u <user account>)
219. Howto delete a user account?userdel -r <user account>
220. Howto find which groups a user belongs to?awk 'BEGIN{FS=":"};{print $1 }' /etc/passwd |xargs groups |sort -k1|more
221. Howto share disks with Windows?man samba ; more; man smbpasswd ; man smbclient (smbclient //win-client/share -U"USER%PASSWD" -c "ls -l" ; mount -t smbfs -o username=XXX,password=YYY //windowsPC/share /mnt ; net use S: \\linux-client\public) ; man smbmount ; smbstatus
222. The systeminfo, the process-info please. (The number stands for PID)Everthing can be found in the pseudo directory /proc. This directory will be empty when you shut down the computer.
223. What is the command for control panel?/usr/sbin/setup (be carefull with X setup)
224. How can I find all the configuration commands?apropos conf | more
225. Why "ls -l" and "du" do not show me the same result for the same file?"ls -l" shows the real size of a file. "du" shows the effective size rounded up to the block. Please read the next question.
226. Howto define the block size on my disk? (the block is the MINIMUM amount in bytes the system can write to a disk, so a 10bytes file will occupy one 4096-block as a 4095bytes file. In dos they call it an "Allocation Unit")mke2fs -n -F /dev/hdXX | grep Block OR tune2fs -l /dev/hdXX |grep Block ; where hdXX is your Linux hard drive
227. Howto make a new ext3 filesystem on my new extra hard drive? (must use the journal option for ext3)mke2fs /dev/hdXX -j -L <label>
228. Howto get I/O statistics from a harddisk?iostat -d -x /dev/hda1 /dev/hda2 5 2
229. I got "invalid magic number in the Super Block" when booting my PC, what should I do?Super Block (infos about files, list of inodes, free blocks etc) is somekind like FAT tables in Dos. Boot in "linux rescue" from RedHat CD1. Type "mke2fs -n -F /dev/hdXX", where hdXX is your / (root) partition (or the defected partition) (use fdisk -l to find out). The command shows you the backup of the Super Block from the defected partition. Use one of them to repair the system: "e2fsck -b BBB /dev/hdXX", where BBB is the block with the Super Block informations you found from the first command.
230. Howto mark bad blocks on my hard drive?e2fsck -c /dev/hdXX
231. Howto setup a new hard driver?run kudzu and then "cat /etc/sysconfig/hwconf", search for device name at "class: HD"; use fdisk to partition the disk; create a filesystem with "mke2fs /dev/hdXX -j -L /newdisk"
232. Howto monitor my SMART (Self-Monitoring, Analysis and Reporting Technology) disks?smartctl -a /dev/hda (smartctl -h)
233. Howto install a SCSI control?Run kudzu, and then run "modprobe" on the module you find at the last line at /etc/modprobe.conf
234. Howto scan a SCSI bus?cdrecord -scanbus
235. Howto get some informations on a scsi device?scsi_info <the scsi device> (can find the device name of a HW device at /etc/sysconfig/hwconf)
236. How to create a mirror system/data disk (RAID)? (very good idea indeed, needs raidtools-XXX.rpm)man mdadm (raidtab is replaced by mdadm) ; google infos about raidsetfaulty, raidhotremove, raidhotadd ; cat /proc/mdstat
237. Howto concatenate several physical hard disks (or raid devices) into a virtual storage pool?man lvm ; man pvcreate ; man vgcreate ; man lvcreate ; man mke2fs ; man pvscan ; cat /proc/lvm
238. Can I resize a partition like in Partition Magic?qtparted (v0.4.1, NB: there are still some limits on ext3)
239. Howto boot in single mode?Clicking here, search for the word "single"
240. Howto make a harddisk bootable?Clicking here
241. Howto make a backup of my whole partition hda1 to hdb2? (a la Ghost in Dos/Windows World)clonezilla OR mount /dev/hdb2 /mnt ; dump 0f - /dev/hda1 | (cd /mnt; restore -xvf - )
242. Howto make a backup of a partition?dump -0f my_backup -z4 /dev/hdXX ; restore it with: restore -xuvf my_backup (use the option -h for a specific directory)
243. Is there a good backup system?
244. Howto copy a filesystem remotely (a la rsync)?(cd /prod; tar -cvf - .) | ( rsh mars; cd /prod; tar -xf - ) OR dump -0f - /prod | (rsh mars; restore -xf - -D /prod )
245. Howto download a whole WWW site in one shot? (a la Offline Explorer)wget -v -p --progress=dot
246. What can I replace ASP with?Use PHP and MySql
247. Howto add f.ex. 22 days to the current date? (needs mysql server)date --date='22 day' OR echo "select date_add(curdate(),interval 22 day) Date;"|mysql
248. Howto subtract f.ex. 120 days from the current date? (needs mysql server)date --date='-120 day' OR echo "select date_add(curdate(),interval -120 day) Date;"|mysql
249. Howmany days are there to Christmas?echo "select to_days('2011-12-24') - to_days(curdate()) 'See you in';"|mysql
250. From "uptime" the server has been up for a while, how to find the date I switched it on?echo "select date_sub(sysdate(),interval '139 22:52:0' DAY_SECOND) DATE;"|mysql (say, the server has been running in 139 days and 22hours)
251. Howto add a number of seconds to a date?echo "select date_add('2004-05-29 18:00:00',interval '6:30:0' HOUR_SECOND) DATE;"|mysql
252. How to calculate by using date?date -d '3 weeks' +"%b %d" ; date -d 'last Sunday';
253. How can I quickly test my php script from a console?echo "<?php phpinfo(); ?>"|php|lynx -stdin
254. What is Phonetic?Some kind like chat, shortening a sentence and cutting the vowel, e.g. "See you late = SYLTR" ; "I love NewYork = ILFNYRK"; try: echo "<?php echo metaphone('I love NewYork')?> "|php
255. Howto create ascii art? (a la those creative signatures you see from the underground. I use figlet-2.2.1-41.suse.i586.rpm; nice fonts: catwalk, crawford, fraktur, isometric, larry3d, roman, speed art)/usr/games/figlet -tcd /usr/share/games/ figlet/fonts/contributed -f broadway ascii OR cd /usr/share/games/
figlet/fonts/contributed ; /usr/games/figlist -d /usr/share/games/
figlet/fonts/contributed | xargs -i /usr/games/figlet -tf {} {} Art
256. Howto create a nice ASCII-box around a text? (needs boxes-1.0-1.i386.rpm)boxes -l AND /usr/games/figlet -tcd /usr/share/games/
figlet/fonts/contributed -f broadway ascii |boxes -ac -d dog
257. I am boring and exhausting, what should I do? (You do nothing and be exhausted, something wrong ;-); to everyone who experiences the same "trouble" as my cousin :-) )Stop gaming, do some creativity like this one: "telnet", make your homework, help your mother and then go to the library
258. Howto Caesar-code a message? (moving every letter a character ahead)echo "from caesar to the mystery cleopatra" | tr '[a-z]' '[b-z]'
259. Who is Socrates? (you must connect to the internet)dict -h socrates (kdict; try "dict: socrates" and "ths: socrates" in konqueror-address-tab too)
260. I have just been recruited by the CIA, the Foreign Affairs department. I need more infos about IraqWow, A spy who loves Linux. Ok connect your micro Linux satellite laptop to the web-channel, type: dict -h -d world02 -s prefix iraq
261. Howto get more info about an element? (you must be online)dict -h -d elements uranium; dict -h -d elements tungsten
262. What does the latin word "vita" mean in english? (you must be online) dict -h -d lat-eng vita ; dict -h -d eng-lat -s regexp \.wor\. ; AND dict -h -D -v
263. Does Linux have a local dictionary?kwordtrans (it uses dictionary files at /usr/share/wordtrans; the best is the Germany-English book of Frank Richter and the latin book by Tyler Chambers)
264. The chinese calendarccal
265. I can't call my partners in LA, do they go bankrupt? :-)Relax, maybe your partners just have a day off for the national holiday, try: gcal -q AU_VI -n (for Australia) ; gcal -q TW -n (for Taiwan) ; gcal -q VN -n (Vietnam) ; gcal -q US_WA -n (USA) ; gcal -q AE -n (United Arab Emirates) ; gcal -q DE_BL -n (Germany) ; gcal -n -q GB_EN (UK) ; gcal -hh|more
266. When do my business partners celebrate their religion holidays?gcal -n --christian-holidays ; gcal -n --orthodox-new-holidays ; gcal -n --chinese-flexible-holidays ; gcal -n --islamic-civil-holidays ; gcal -n --hebrew-holidays ; gcal -n --persian-jalaali-holidays
267. I know many Windows applications, can I find those in Linux?Linux - Windows equivalents
268. Is there an application a la Microsoft Money?gnucash
269. Is there an application a la Thumb Plus?gthumb
270. Is there an application a la Hyperterminal?minicom, tip, cu
271. Is there a good picture manipulation application a la PhotoShop/Picture Publisher?gimp
272. Is there an application a la Pagemaker?scribus
273. Is there an application a la Cubase (audio & midi sequencer)?rosegarden
274. I want to capture all the movement on my PC for making an instruction. Is it something like Windows Camstudio?gvidcap
275. How to test my firewire device?testlibraw (from the package libraw1394-0.10.1-1)
276. Howto ray trace my own design? (needs povray-3.50c-5.i686.rpm)povray +I/usr/share/povray-3.5/scenes/textures/finishes/balcony.pov +Obalcony.jpg +W1024 +H768 +V -D +X (took about 18min on a P4-1.8GHz) ; kuickshow balcony.jpg
277. Is there a good drawing tool a la Corel Draw/Visio?xfig (very good) or dia for diagram (dia*.rpm)
278. Howto quickly create a label for my web site? (needs ImageMagick; font path can be found with "chkfontpath")convert -background lightblue -fill blue -font /usr/share/fonts/ttf/Perspection.ttf -point size 75 label:Welcome welcome.png
279. A great one from ImageMagick (the design of Anthony Thyssen)convert -size 320x120 xc:lightblue -draw "fill tomato circle 250,30 310,30 fill limegreen circle 55,75 15,80 font /usr/share/fonts/ttf/ALLEMBER.ttf font-size 72 decorate UnderLine fill dodgerblue stroke navy stroke-width 2 translate 10,110 rotate -15 text 0,0 ' Anthony '" anton.png
280. Is there a "download accelerator" feature in Redhat?Konqueror and Netscape supports the resume operation, so the download starts at the point where it stopped
281. Does Linux has a good mail client?mutt, kmail, evolution, pine, elm
282. Is there a html editor a la FrontPage?quanta from KDE or Bluefish
283. How can I open/write a MS word document?OpenOffice, KOffice or StarOffice
284. Howto get a good picture viewer a la Acdsee32?kuickshow OR gqview --slideshow <path to your images>
285. Does Linux has something a la 3DStudio?moonlight3d; kpovmodeler ; The excellent blender3d from The Nederland ; AC3D; LinuxArtist ; Bellevue artists
286. Is there a light application a la Paint Shop Pro?display
287. Is there an application a la MS-project?planner ; Planner (the former MrProject)
288. Howto quickly print the word hello 100 times?yes hello |head -100
289. I am alone 100m above the ground, my cell phone is broken, howto contact my colleague on the ground.write user ttyX ; e.g. "write jane tty2"
290. Howto print only lines with more than 10 characters?awk 'length > 10' <file name>
291. How can I read backward as good as Leonardo da Vinci?echo "mississippi impossible" |rev
292. How to say "Hello" to the aliens from the Xunil Galaxy? (use copy/paste)perl -e 'use POSIX;print $i=pack(c6,(36*2), ceil(100.68), (unpack(c,h)+4), (oct ("0b1101100")), ( hex("6f")) ,10); '
293. Howto convert a file from lowercase to uppercase?cat <file> | tr '[a-z]' '[A-Z]'
294. Howto make a dice?perl -pe 'use POSIX; print ceil(rand 6)."\n"'
295. Want a primitive elapse watch?while true; do clear;date; sleep 1; done
296. Howmany days since January 1, 1970? (use it to find the expired date from your passwd file)echo `date '+ %s'/86400`|bc
297. Howto reverse the output so bottom becomes top?tac <filename>
298. Howto read (not write) the CDs from Roxio/Adaptec's DirectCD (meaning the session is not closed)?mount -t udf /dev/cdrom /mnt/cdrom (mount the CD with the UDF filesystem; only for CDBurn without the "SCSI host adapter emulation" option in grub.conf)
299. Howto create an iso file?man mkisofs OR xcdroast
300. Howto get my hotmail/yahoo mails without opening a web browser? (run the perl script from the console, it downloads all the mails into your mailbox, you can then read them (offline) with kmail without any waiting. Very good.)gotmail (for Hotmail) ; FetchYahoo
301. What is the best spam killer?Try spamassassin-2.63-8.i386.rpm in cooperation with procmail
302. Howto collect status from remote hosts?rup (must install the rusers-server*.rpm package on all hosts)
303. Howto remote-mount a filesystem with Midnight Commander?Install the mcserv*rpm package (RH7.2) and restart the portmap service (if it fails, check your firewall) before starting the mcserv daemon. Run mc and press F9/Network link and then enter the remote IP addr.
304. Howto read/write linux ext2/ext3 partition in Windows98?John Newbigin's Explore2fs
305. Howto debug a korn/bash shell script?ksh -x filename.ksh (bash -x)
306. How to find lenght of a password in a korn script?read pwd; length=${#pwd}
307. How to call an oracle (sql) script from a korn shell?export ORACLE_SID=XX;export ORACLE_HOME=/XX; sqlplus user/passwd <<EOT ; set serveroutput on; set pause off; spool /tmp/out; select date from dual; spool off; exit; EOT
308. If you get "TNS:could not resolve the connect identifier specified (DBD ERROR: OCIServerAttach)" (DBD::oracle)Change the dbh to the format with "host", eg: my $dbh = DBI->connect("dbi:Oracle:host=;sid=","scott/tiger", "");
309. If you get "Premature end of script headers:" (cgi/perl via http)Your cgi file is not a pure "ASCII text", but a "ASCII" with "CRLF line terminators". Add an empty line at the top at your cgi file; run "file <my cgi file>"
310. How to restore a session after the connection was down?using "screen" to start your shell, Clicking here
311. Howto create a BIG file for test purpose (ftp, hardware (time))? (XXX=filesize in Mbytes and XXX < total RAM ; ignore the warning; use copy/paste)ulimit -f `echo XXX*1000000/1024|bc` ;cat /dev/hda1 > big_file ; ulimit -f unlimited (or just dd if=/dev/hda1 of=/tmp/big_file bs=1024 count=5000)
312. Which libraries a particular application is using?ldd `which XXX` ; where XXX is the name of the application
313. Which libraries are on my system?ldconfig -p
314. Is there a tool for LDAP?jxplorer, gq
315. Howto write in colour on a text console? (BG;FG;Attribute ; 30=40=black 31=41=red 33=43=yellow etc ; 00m=default 04m=underline 05m=blink ) echo -en "\033[46;33;01m" Hello World "\033[00m\n" OR echo -e '\e[1;31mHello \e[44;34mWorld \e[0m' OR perl -e 'use Term::ANSIColor; print colored("Hello World\n", "bold green")'
316. Howto test my syslog facility and priority setting? (man syslog.conf)echo "Hello, goodbye" | logger -p kern.crit (then make a tail on /var/log/messages)
317. Howto test the speed of my new accelerator graphic card?glxgears ; glxinfo (tuxracer)
318. Is there a video editing software l Pinnacle Studio or Adobe Premiere?kino
319. Howto add 2 wav/mp3 files? (in "kino/audio/mix" it accepts one file only)cat <my sound1.wav> <my sound2.wav> > all.wav
320. Howto capture my video sequence from a webcam?ffmpeg -vd /dev/video -ad /dev/sound/dsp -s 367*300 -r 9 -t 120 my_video.avi (record in 120s with 9 frame/s; replace them with your correct device file)
321. Howto convert the avi format to the mpg format (mpeg1)?ffmpeg -i my_video.avi my_video.mpg (for mpeg2: ffmpeg -vcodec mpeg2video -i my_video.avi my_video.mpeg)
322. Howto convert an avi file (mpeg1, mpeg2 etc) back to raw data (the DV format), so I can edite it with "kino"? (needs the package -vcodec dvvideo -i my-file.avi my-file.dv (try "ffmpeg -formats")
323. Howto convert a raw data file to mpeg2?ffmpeg -vcodec mpeg2video -sameq -i 001.kinofx.dv <my-video.mpeg>
324. Howto grab sound from an avi file (with divx, mpeg2 encode)?ffmpeg -acodec mp3 -ab 128 -ar 44100 -i <my_movie>.avi <my_music>.mp3
325. How to get more infos from my divx files?mplayer -v <my-divx.avi>
326. How to easily/quickly cut the intro and the end of my mpeg2 movie (ok with mp3 too)?using "vi" (yes "vi" is a great candidate against Pinnacle Studio too :-) , had tried on a 750MB without any problems. Using "wc -l" to get a feeling howlong you should cut)
327. Is there any tools for helping me to improve/check my "regular expression" skill?kregexpeditor OR Use "Regular Expression Editor": Open a text file in Konqueror/<ctrl+F>/click "Regular Expression"/click Edit ; use the tools on the top to create your expression on the editing area, the result is at the bottom
328. I want to be a good sed ; man awk ; (man perl)
329. Howto get a Linux system running without knowing anything about Linux, or anything about any configurations and do not have any hard drive? (good for a diskless enviroment, can use it to replace netbooting)Use the wunderbar Knoppix or DemoLinux
330. Howto connect to a terminal server?rdesktop (rdp protocol)
331. Howto get a higher resolution on a console?Append "vga=773" at the end of the line "kernel" of the Grub's /boot/grub/grub.conf
332. Howto find who owns a domain name/web site?whois
333. Howto test that I have a particular perl module?perl -e 'use XXX::YYY' ; where XXX::YYY is the perl module
334. What is the atomic weight of an element just like gold?units gold (vi /usr/share/units.dat)
335. Howto convert the different units like inch, meter, pound? (more /usr/share/units.dat)units 1in cm; units 1feet m; units 1pound kg; units 1mile meter; units 1gallons liter; units "2 days" seconds; units earthmass; units c (the speed of light); units match (sound speed); units metriccarat (jewel); units 20degC degF; units marathon; units electrichorsepower; units A4paper; units quarternote (music)
336. What is the country code for Vietnam?grep -i vietnam /usr/share/zoneinfo/ (who has IL? "grep -iw il /usr/share/zoneinfo/
337. What is the latitude and longitude in Copenhagen?grep -i copenhagen /usr/share/zoneinfo/
338. What is the TZ environment variable for Singapore?grep -i singapore /usr/share/zoneinfo/
339. Howto convert dos-text-format to unix-text-format? (the difference between Dos & Unix format is: "a dos new line" (an Enter) contains a LF (line feed) plus a CR (carrige return), when "a unix/linux new line" only has a LF)dos2unix <filename>
340. Howto print number for each output line?cat -n <filename>
341. Howto filter duplicate lines in a text file?sort -u <filename>
342. Howto sort the 11th position of the 3 column?sort -nk 3.11 <my file>
343. Is there a terminal calculator?bc -l (try 1/9; try 2^32 ; the doubling function for a population increment of 2% yearly: l(2)/l(1.02) (yes, in 35 years) ; for an increment of 0.7% yearly (Denmark): l(2)/l(1.007) equals 99 years
344. Howto lock my working console?vlock
345. Howto make a dialog box?kdialog --yesno "Let it be" ; dialog --calendar Hello 0 30 14 07 2003 ; dialog --yesno "Are you ready?" 10 20 ; xmessage -center "Hello World" -timeout 5
346. Howto quickly find the biggest files in a directory? (the unsort output saves in /tmp)du -k /home/ |tee /tmp/a.txt|sort -nk1
347. Where can I find the flags of the world? (needs the package wordtrans-1*)gqview --slideshow /usr/share/wordtrans/flags (use the two keys "PageUp" and "PageDown" to go quickly through image files)
348. Howto print with columns?column; colrm; join; merge; paste - - -;
349. Howto watch changes of a webpage? (i.e. you want to update the news every 5min)watch -n 300 lynx -dump
350. Advanced system admin files/directories/boot/grub; /etc/hosts; /etc/inittab; /etc/rc.d; /etc/xinetd;
/etc/sysconfig; /etc/X11/XF86Config (xorg.conf); /var/log; /proc;
351. Howto see what an application doing? (a very strong command)strace < Your app> >& trace.log
352. I have one runaway process, it spawns many other child processes with the same name. How to kill them at once?killall -9 XXX or ps -ax|grep XXX|awk '{print $1}'|xargs kill -9 ; XXX is the NAME of the runaway process. Test it without the last pipe to be sure you not kill the wrong one.
353. How can I use the different signals on a running process?man 7 signal
354. Howto make a backup on my home directory to a file?dump -0f my_backup -z4 /home/jane OR using afio OR amanda
355. How to restore the backup file?restore -xvf my_backup (enter 1 for the question "Specify next volume #:" ; use interactive -i (?,add,extract) if you only want to restore some files)
356. How can I tune/tweak the kernel?system-config-proc
357. How to find opened ports? (use firewall to protect them)nmap localhost (nmap -p 1-6000 192.168.0.*) ; socklist; netstat -tln ; netstat -an
358. Howto find which application opens which port?lsof -i UDP:636; lsof -i TCP:22
359. Howto test an udp connection, is it open?nmap -p 123 -sU -P0 <hostname>
360. Does Linux have something a la Sun's ndd?ethtool
361. Howto list the statistic from my network?netstat -s
362. Howto find which application/daemon opens which port? (socklist is from procinfo*.rpm)socklist |sort -k2 -n
363. Howto close an opened port?To open a port means to have a service/application running (read the previous question). Just stop or kill the service then the port close. Test it with "nmap localhost"
364. Howto find which computers connect to my server?clear; tput smso;perl -e '$a="Foreign Address";$b="Local Port";printf"%-20s\t %-20s",$a,$b';tput rmso;echo -e '\n';netstat -tn|sed -n '3,$'p|awk '{printf("%-20s\t %-20s\n", $5,$4)}'|sort -n OR "netstat -a|grep telnet"
365. Howto use signature for my web server and howto encrypt my mail?man gpg (try: gpg --list-keys)
366. Howto get security alert and howto update it? (required internet access)up2date (new security alert arrives via mail)
367. Howto install a firewall?system-config-securitylevel ; lokkit
368. What is the best tools to protect and improve my network against intruders, somekind of "Intrusion Detection Systems"?snort ; ethereal ; tcpdump ; netwox; nc; sniffit (use it with: swatch, netstat, socklist, nmap, nc)
369. How to listen to the net traffic with tcpdump?tcpdump -i eth0 tcp port 22 (listen on port 22 of interface eth0)
370. Are there any good virus scan?Try BitDefender, Avast, ClamAV, Sophos.
371. Howto share a Redhat internet connection with windows clients? (using ipchains; ipchains is replaced by iptables in Fedora2) Clicking here
372. Howto quickly protect my PC against the internet (with iptables)?Use Jamin W. Collins's Firewall script. It is not a tutor, but an interface to iptables. Use 200 minutes then you are safe (and use tripwire fingerprint, chkrootkit then you can sleep during the night :-)).
373. Howto quickly make a fingerprint (a la tripwire; to make sure nobody has compromised your orginal system commands) of my important/vulnariable directories? (/bin, /sbin and /usr/sbin)Very simple, just make a list of the directory and save it on a floppy disk. a) ls -l /bin/* |gzip -c > /mnt/floppy/bin_dir.gz b) do it for other directories. When you want to check your system, just do step a and b again and compare those with the backup on the floppy. Use zdiff <bin_dir.gz> <bin_dir_new.gz>
374. Howto close for login access on my server during the night (and at the weekends)? (avoiding nightly cracking activity; remember to patch all the security holes/exploit)Create a system admin account "sysadm" (check to see if you can "su" from it); add "account required /lib/security/" at /etc/pam.d/login ; add "login;tty*;!sysadm;Wk|2100-0600 " at /etc/security/time.conf
375. How to easily update/patch my server? (Better using apt than yum, since yum is primarily for fedora. up2date is only for Redhat-Enterprise; if "apt-get install XX" not work, try "yum install XX" instead)get the conf file from (get the right repositor for your fedora release); apt-get update (the base can be found at /etc/apt/sources.list.d/); apt-cache search mplayer; apt-get install <xxxx>; to upgrade the whole system: apt-get upgrade
376. I get error when starting portmap ;OR some of the applications/games do not work on the network.Your firewall is probably blocks for some of the port. Try to stop the firewall: service ipchains stop (or iptables).
377. Howto use/repair GRUB and howto use it as a boot manager (about MBR, disk structure)?Clicking here
378. Howto build a new kernel?Kernel-HOWTO
379. How to avoid my bandwidth bombard with mp3 traffics, something like bandwidth limiting?Clicking here
380. Howto use spamassassin to filter spam mails?Clicking here
381. Howto synchronize my workstation's directory (a regular user, NOT root) with my laptop like Briefcase in Windows? (On both machines: chkconfig rsync on ;chkconfig rsh on ;service xinetd restart AND add the hostname you trust to /etc/hosts.equiv). Sync all files from /usr/fy on the workstation to the /home/fy on the laptop with the hostname bi.rsync -auvz /user/fy/* bi:/home/fy; rsync -auvz bi:/home/fy/* /user/fy (BTW the two actors Fy & Bi had given me many "happy hours" during my growing up).
382. Howto quickly distribute (close to "Remote Installation Service") a Redhat installation?ksconfig (Kickstart)
383. Is there any good IDE (Integrated Developer Enviroment) for Linux?kdevelop, CodeForge, Glade, Kylix, Dev-C++ and Motor
384. Is there a good documentation/code demo for Trolltech-Qt X-Window-programming (Kde)?qtdoc/assistant (qt-devel-3.1.1-6)
385. Is there a good code demo for Gnu-gtk X-Window-programming (Gnome)?gtk-demo (gtk2-2.2.1-4)
386. How can I collect system statistics from my server? (needs the sysstat-5.0.1-2.i386.rpm package)run /usr/lib/sa/sa1 every 10min (using crontab; see /etc/cron.d/sysstat), it collects the statistics and appends them at /var/log/sa/saXX (XX is the date). Using "sar" to display the statistics (sar -A; sar -b) and "man sa2"
387. Howto trim all my old temporary files (more than 3 weeks; put it in your crontab)?find /tmp -mtime +21 -exec rm {} \;
388. How to find all the new files with the word "CPH" from 5 hours ago?find /root -cmin -300 -exec grep -li CPH {} \;
389. Howto find all programs with setuid (man setuid)?find / \( -perm +2000 -o -perm +4000 -o -perm +6000 \) -o -fstype nfs -prune
390. Howto grep a string from a directory with all its sub directories? say we want to find the string "hostname" from /etcfind /etc -exec grep -li hostname {} \;
391. How to find all the files which were changed for the last 3 days (using +3 for more than 3 days)?find ~ -mtime -3 \! -type d
392. How to create multiple directories at once? (creating directories aa,bb,cc,dd and 2 subdirectories for cc) mkdir -p /home/test/{aa/xx,bb,cc/{yy,zz},dd}
393. Howto patch a file from a patch file? (cat the patch file, you then can see what it does. NB: the patch file is the output from "diff"))patch < <the patch file> (get the differences of the 2 files: diff -u <file1> <file2> >patch.diff)
394. Howto build a rpm package from a source file (*.src.rpm)?rpmbuild --rebuild *.src.rpm (output can be found at /usr/src/redhat/RPMS/ ; source code at /usr/src/redhat/SOURCES)
395. Howto solve the ld error during a compile? (if you got an error something like: /usr/bin/ld: cannot find -lelf or /usr/bin/ld: cannot find -lselinux )The reason is that the developer package is not on the system; look for the packages with the name elf or selinux from the Fedora CDs (just use "grep selinux TRANS.TBL"). Install the missing developer package and then try "make" again
396. How to build a cheap and green energy web server (less than 4 watts)?;
397. How to get through the Windows proxy with MS Authentication Protocol NTLM?
398. How to made a VPN server? OR
399. Any VPN client application for the Cisco vpn concentrator?vpnc, KVpnc
400. What about Virtualization in Linux?KVM, OpenVZ, Virtuozzo, Xen GPL, KVM, QEMU, VirtualBox
401. How to find a valid email adress?grep '[a-zA-Z0-9]\{2,\}.@..*\.[a-z]\{2\}' <file>
402. Making a statistic of lenghthy of the word in a wordlist.for i in `seq 1 32`; do echo "There are" `egrep '^.{'$i'}$' /usr/share/dict/words | wc -l` "$i-letter words in the dictionary." ; done
403. Show me a "chain" command that Richard Pryor will say "Wow" (remember RP in "Brewster's Millions"? The scene where he asked a decorator to spend thousand of dollars for decoration a "5 minute" rum); use copy/paste in Konqueror ; you need perl: perl-5.6.0-17.i386.rpm; replace the 2 last with "last -f /var/log/wtmp.x" for previous months.clear;last|tail -3|tail -1|awk '{print "Statistics from "$3" " $4" " $5"\n"}';last| perl -e 'while(<STDIN>){if (/^(\S*)\s*.*\((.*):(.*)\).*$/){ $h{$1} += $2; $m{$1} += $3;$l{$1}++;}} foreach $user(sort(keys %h)) {$h{$user} +=int($m{$user} / 60); $m{$user} %=60; printf"User %-8s login %05d:%02d hours, total logins %04d times\n", $user,$h{$user}, $m{$user},$l{$user};}'|sort -rk7
404. Do you have one for Gene Wilder too? (use copy/paste in Konqueror; you need perl: perl-5.6.0-17.i386.rpm). NB: there are in average 4-10 objects (gif, jpg, png etc) on a webpage.clear; head -1 `ls -tr /var/log/httpd/access_log*|head -1`|awk '{print "Statistics from " $4$5 "\n"}'; cat /var/log/httpd/access_log*| perl -e 'while(<STDIN>){if (/^(\S*)\s*.*/){ $logins{$1}++;}}foreach $pc(sort(keys %logins)){ printf "The machine %-15s got %05d objects from your web server\n",$pc, $logins{$pc};}'
405. The server's disk is filling and filling, the server will break down very soon. How can I find which process causes it? (do it twice and change 500000 with an another byte-size depending on your situation and replace the word "lib" with "ZZZ" if you want to have the lib files on the output)clear; perl -e '@data=`lsof`;foreach (@data) {@f=split;if ($f[6] > 500000 && $f[8] !~ "/lib/") {print $_;}}'
406. I am a romantic guy, howto define the date of moonlight? (The 15th in a month of the Chinese calendar is always a fullmoon day; Thanks to John Conway for his simple moon rule (85% of the results with 100% hit) and John Walker for his moontool). Replace YYYY with the year you want (2000-2019 only). Use copy/paste in Konqueror.echo YYYY|awk 'BEGIN{m=1;d=1;};{c=substr($0,1,2);y = substr($0,3); mod=y%c;mod*=11;mod%=30;printf("\nFull Moon %d (+/- 1day) ONLY for Feb2000-Dec2019\n\n",$0); while (m<13){ while(d<32){if(m<3){m2=m+2}else m2=m;fase=mod+d+m2;if(fase==53 ||fase==23){printf("%-2s: %d\n",m,d);d=1;break;}d+=1;}d=1;m+=1;}}' OR gcal -n --chinese-flexible-holidays OR ccal
407. Howto control/limit my consuming of an internet connection? (say you get 120 minutes for each connection; if you have an another value change the b=120 to that value)ps -eo "%t %c"|grep pppd|awk '{print $1}'|awk 'BEGIN{FS=":";};{ if(NF==1){printf("You have 2 hours\n");exit}; if(NF==2){h=0;m=$1}; if(NF==3){h=$1;m=$2};t=h*60+m;b=120-t; h=b/60; m=b%60; printf("You have %d hours and %d minutes back\n",h,m);}'
408. Howto find the word frequency of a text file? (use it to find out how good your students are and how good you are to teach)cat <file name>| perl -e '$/ = " "; while(<STDIN>){ tr /A-Z/a-z/ ; @ww=split; foreach $w(@ww) { $t++; $ar{$w}++; }}foreach $w(sort (keys %ar)) {print "$w $ar{$w} \n";} print "$t total words found \n";'|sort -nrk2| more
409. How to rename my jpg files to sequential files (e.g. pic1.jpg, pic2.jpg, pic3.jpg etc)? Replace XXX with the name you want to use.perl -e '$n=1;@data=`ls $ARGV[0]`;foreach (@data) {@f=split(/\./);chop($a=$_);$c=$f[1];system "/bin/mv $a $ARGV[1]$n.$c";$n+=1;}' \*.jpg XXX
410. Howto get a TOP25 of downloaded files from my public ftp server? (use copy/paste)clear; echo -en "\033[40;32;01m";head -1 `ls -tr /var/log/xferlog*|head -1`|awk '{print "Statistics from " $2" "$3" "$5 "\n"}'; cat /var/log/xferlog*|perl -e 'while(<STDIN>){if (/^\s*.*\s+(\/.*)[ab]+.*/) {$n{$1}++;}} foreach $file(sort(keys %n)) {printf "File %-44s downloaded %04d times \n", $file, $n{$file};}'|sort -rk 4|head -25;echo -en "\033[00m"
411. Howto monitor my disk usage? (change 90 to an another value suit to your need; the value is in percent from the command "df"; put it in a script/crontab ; only for bash shell, use copy/paste)R=$(perl -e '@d=`df`;foreach(@d){@f=split;print "$f[0]\n" if$f[4] >90;}'); if [[ $R != "" ]] ;then echo Full Disk: $R ;else echo No problem;fi
412. Howto change the first lowcase character of a filename to an uppercase one? (reverse it by changing "y/a-z/A-Z/" to "y/A-Z/a-z/")perl -e '@data=`ls $ARGV[0]`;foreach (@data) {chop($a=$_);@f=split(/ */,$_,2);$f[0] =~ y/a-z/A-Z/;system "/bin/mv $a $f[0]$f[1]"}' <the files you want to change, i.e. \*.jpg for only jpg files)
413. Howto change all the filenames from the current directory from uppercase to lowcase? perl -e '@data=`ls $ARGV[0]`;foreach (@data) {chop($a=$_);$b=$a; $a =~ y/A-Z/a-z/;system "/bin/mv $b $a"}'
414. Why did the HomeBanking system not accept my "giro form" payment? (probably because the checksum on the giro-form is wrong (using modulus 2). Replace XXX with all the numbers (14 of them) from the giro, EXCEPT the LAST figure (the 15th). The last figur is the checksum, compare it with the result from the awk script.echo XXX |awk 'BEGIN{i=1}{while(i<=14){num=substr($0,i,1); if(i%2==0)n=num*2; else n=num;if(n>9) {s1=substr(n,1,1);s2=substr(n,2,1); n=s1+s2} s=s+n;i+=1}} END{print s;if(s%10==0) r=0; if(s<10)r=10-s;if(s>10 && s<20) r=20-s; if(s>20 && s <30)r=30-s; if(s>30 && s<40)r=40-s;if (s>40 && s <50) r=50-s;if(s>50 && s<60) r=60-s;if (s>60 && s<70)r=70-s;if(s>70 && s<80) r=80-s;if(s>80 && s<90) r=90-s;if(s>90 && s<100) r=100-s;if(s>100 && s<110) r=110-s;if(s>110 && s<120) r=120-s;if (s>120)r=130-s;print "The checksum is: " r}'
415. Howto stress-test my CPU? (use "top" to check it out; break with ctrl+c; more stress: change the number 4 to, say 9) (sorry, access to kcore/mem is forbidden from Fedora core2!)while true; do if [[ `ps -ef|grep -w "/proc/kcore"|grep -v grep|wc -l` -lt 4 ]]; then {( dd if=/proc/kcore of=/dev/null &)} ;fi;done
416. Howto stress-test my CPU (version 2)?while :;do :; done
417. Howto make a BIG ramdisk ( say 300MBytes ( I suggest only use 90% of the total RAM ) ; you are able to create 16 ramdisks : /dev/ram0 ,
/dev/ram1 .. /dev/ram15 ) ?
Add "ramdisk_size=300000" at the end of the "kernel" parameter at /boot/grub/grub.conf. Reboot your PC ; mkdir /mnt/ramdisk ; mke2fs /dev/ram0 ; mount /dev/ram0 /mnt/ramdisk
418. Howto stress-test my RAM? (needs a BIG ramdisk (see above) and use "ls -l /mnt/ramdisk/BIG" to check) (sorry, access to kcore is forbidden in Fedora core2, using /dev/mem)while true; do if [[ ! `df -k /mnt/ramdisk/ | awk '{print $5}' | tail -1| awk 'BEGIN{ FS="%" } ; {print $1}'` -eq "100" ]]; then { (dd if=/proc/kcore of=/mnt/ramdisk/BIG) } else { (rm -f /mnt/ramdisk/BIG) }; fi; done
419. What is Doomsday? (it is the "same" day of the week of the following dates: 4/4, 6/6, 8/8, 10/10, 12/12, 5/9, 9/5, 7/11, 11/7 AND Jan/3, Jan/31 (for leap years it is Jan/4, Feb/1). Doomsday for 2005 is a Monday, for 2006 it is a Tuesday. With the help of Doomsday you can quickly calculate the day of a week of a given day without a calendar, impress your friends at a party :-). Thanks to the Princeton mathematician John Horton Conway). Replace YYYY with the year you want (2000-2099 only))a=$(echo YYYY| awk '{i=substr($0,3);q=int(i/12); r=i%12; q2=int(r/4); printf("%i",q+r+q2) }') ;echo "select DAYNAME(date_add('2004-01-06',interval $a day) )"|mysql
420. Howto write an "animated time glass" for a none graphic applications? (the code is not mine but from the internet)clear; str=("/" "-" "\\" "|"); x="0"; echo -e -n "Working "; while true; do echo -e -n "\\b${str[$x]}"; x=$(((x+1) % 4)) ; sleep 1; done
421. Howto convert unix time to ordinary time? (e.g. 1094740770, 1094692376)cat <my log file> |perl -e ' while (<>) { @data=$_; @f=split; $a=@f[0]; ($sec,$min, $hour,$mday, $mon,$year, $wday,$ydat, $isdst) = gmtime($a); $year += 1900; $mon += 1; $hour += 2; print "$year-$mon-$mday $hour:$min:$sec ", $_ ; }'
422. How to right-justify columns in my file? (say, there are 6 columns max 9 characters each in the file)awk '{OFS="\t"}{printf("%10s %10s %10s%10s%10s %10s\n",$1,$2,$3,$4,$5,$6)}' <my file>
423. How to find the day of Easter Sunday?echo YYYY|awk '{y=$0; m= (((y-y%100)/100)-((y-y%400)/400)-((y-y%300)/300)+15)%30; n= (((y-y%100)/100)-((y-y%400)/400)+4)%7; a= y%19; b= y%4; c= y%7; d= (19*a+m)%30; e= (2*b+4*c+6*d+n)%7; eastsun=22+d+e; eastmth=3; if(eastsun > 31){ eastsun-=31; eastmth=4}} {printf("\nEaster Sunday for %s is the %2d of %2s\n\n",y,eastsun,eastmth)}'
424. XX Magic
425. X WindowTry to be familiarized with all the menus in the X Window.
426. Howto change resolution, color depth, graphic driver for my display?From type: system_config_display
427. Howto restore the KDE layout in Fedora's BlueCurve? (possible with auto-login without password)Clicking here
428. How does the X-Window work?more `which startx`
429. Show me some shortcuts in KDE, please.Start-menu (ALT+F1); Run (ALT+F2) ; Show/unshow Desktop (CTRL+ALT+d); Switch between applications (ALT+TAB) ; Close application (ALT+F4) ;Switch between virtual screens (CTRL+F1 F2 etc) ; Process manager (CTRL+ESC) ; Lock PC (CTRL+ALT+l) ; Quit Window (CTRL+ALT+Backspace) for more see ~/.kde/share/config/kdeglobals
430. Please show me some great shortcuts in konsole.New session (<CTRL+ALT+n>) ; switch between session (<SHIFT+L/R keys>) ; Paste (<SHIFT+Insert>) ; Menu (<CTRL+ALT+m>) ; Name a session (<CTRL+ALT+s>) ; Search previous commands in history (<CTRL+r>)
431. What about some useful shortcuts in konqueror?Find (<CTRL+f>) ; Home (<CTRL+Home>) ; Goto address bar (<ALT+o>) ; Go back (<ALT+L/R keys>) ; New window (<SHIFT+CTRL+d>) ; Bookmarks (<F9>) ; Send link (<CTRL+l>) ; Google (<F6 and type gg: redhat FAQ tips)
432. I have installed KDE, GNOME and WindowMaker. Howto switch from the one to other?switchdesk <KDE> OR less ~/.Xclients or less /etc/X11/xinit/Xclients
433. Howto add new applications in the K-Menu? (the left-bottom icon)kmenuedit
434. Where can I find the links of the apps from the K-Menu? (the left-bottom icon)/usr/share/applnk and /var/lib/menu/kde
435. My X Window could not start, I got a black screen or just an error.Wrong screen resolution or missing X config file or wrong mouse type. Rerun mouseconfig (start with a standard mouse) or rerun system-config-xfree86 (if you are doubt, set the VERTICAL SYNC between 50-70 for an old monitor. A good idea is to manually enter (not use the auto setting) the exact values for both HOR/VER sync from the Monitor's User's manual). Escape with <CTRL+ALT+Backspace> if the screen flicker too looong.
436. Where is the configuration file for X?/etc/X11/xorg.conf (man xorg.conf) ; good idea to make a backup of it. The log can be found at /var/log/Xorg*.log
437. Howto make a shortcut?Do it from the file manager Konqueror and drag the file to the desktop while keeping the left buttom down.
438. I want to make a backup of my bookmarks/link-favourite, where is it?cd ~/.kde/share/apps/konqueror/bookmarks.xml
439. I don't want to boot in X Window. I want to boot to a console.1) Hit CTRL+ALT+F2 2)login as root 3)replace number 5 with number 3 at line
"id:5:initdefault:" of the file /etc/inittab
440. Where are the binary X files?cd /usr/X11R6/bin
441. Howto set preferences for the X display?man xset
442. Howto get a font viewer?kcharselect
443. Howto disable screensaver in Window?kcmshell kde-screensaver (X Window)
444. Where are the directory of the Desktop? (all files placed in this directory appear automatic on the desktop)cd ~/Desktop ( "cd ~" means: go to your home directory)
445. How can I auto-start my application when entering X Window?Put a link in ~/.kde/Autostart . For example if you want to start "kmail" type the following at the mentioned directory "ln -s /usr/bin/kmail kmail", then a link will be created (use "which" to find the whole path for an application).
446. Howto change the fonts?kcmshell kde-fonts
447. How to install and understand fonts in Linux?Clicking here
448. What is the command of the KDE control center?kcmshell --list
449. I need capture/screendump my windowsksnapshot (jus press the "Print-Screen"-buttom when using Gnome)
450. Is it fast to use Wine emulator for Windows applications?Yes, it takes 2s for opening Agent, 3s for Downloading Accelerator, 5s for Oxford Dictionary, 4s for Notetab (on a 1.8GHz P4)
451. Howto open a Windows help file?winhelp (need wine*rpm)
452. Howto get Windows Dos prompt? (needs Wine.XX.rpm and wine must set correctly at ~/.wine/config)wcmd
453. Howto get the informations from the Windows Registry Database? (needs Wine.XX.rpm)register
454. Is there any tool to help me with my poor imagination :-)? or Is there a good plot application to help me with my math?scilab; gnofract4D (Mandelbrot) ; octave ; sage ; Euler Math Toolbox ; scilab ;the amazing powerful "gnuplot" (try: set polar <enter> plot [-.4*pi:12*pi] t <enter> ; Try them too: plot [-73*pi:.2*pi] t*sin(t) ; plot [-173*pi:1*pi] t*sin(t) ; plot [-.01*pi:74*pi] t*sin(t); plot [-36*pi:3*pi] .5+1*cos(t) AND FOR 3D: set parametric;splot u,v,u**2-v**2)
455. Howto install the fast & popular Firefox and its plugins (java, realplayer, flash, acrobat) on my Linux distribution?Clicking here
456. Howto add a new java plugin in Netscape/Konqueror?Use the enviroment variable NPX_PLUGIN_PATH (e.g. export NPX_PLUGIN_PATH=
Put it in /etc/profile at the second line)
457. How to listen to the Sky net radio from console ?(needs mplayer)streamtuner2, drradio -C sky (download the python script from
458. I am an european accountant, how can I change the dot on the numeric keypad to a comma for easy my work? (NumLock is on; type the words in the quotes in ~/.xmodmaprc and add "xmodmap .xmodmaprc" in ~/.bashrc for permanent solution)xmodmap -e "keycode 91 = comma" ; X Window, to go back replace "comma" with "period"
459. Some funny/small X programmes?xeyes; xmail; xwininfo; ksnake; xmag; xsnow; tuxracer (needs an Accelerator graphic card) ; Maelstrom ; xboard
460. Does Linux have "Network Neighborhood" like in Windows?Yes, you need to install Samba and LinNeighborhood-0.6.X.rpm
461. Is there any good web admin tool?
462. Howto get a statistic page from a router/laserjet (via a web browser) without I need to do anything (crontab controls it)?Run Xvfb on DISPLAY "5" in the background (Xvfb :5 -screen 0 1024x768x8 -pixdepths 8 -fbdir /tmp), write a script to start the browser (for example: "konqueror -display :5 http://xxx-laser:1234/stat"), save the framebuffer from Xvfb (use option fbdir). To view the framebuffer use the command "xwud -in /tmp/Xvfb_screen0"
463. How to connect to a server via X?On the server: xhost +<name of the remote host> ; on the client: 1)startx 2)telnet <server> 3)export DISPLAY=<client's IP address>:0:0 4)run an X app: xeyes
464. Howto use auto-login in X Window without using password?Clicking here
465. Howto configure my X-Window login?kcmshell System/kde-kdm
466. Howto configure my X-Window logout?kcmshell Components/kde-kcmsmserver
467. My konqueror (KDE) will not start, it just die after 30 seconds. No log no core dump.Rename /etc/X11/xorg.conf and rerun system_config_display. An another reason is: There are some corrupts in your references at ~/.kde. The easy way to solve this problem is to delete that directory (yes, you will lose all the old KDE setup, just like your modem setting, your personal background etc. A good idea to make a copy of ~/.kde before something go wrong.
468. Howto start a second Window Manager? (if you like to try an another Windows Manager with KDE)1) install the Xnest package 2) inside a KDE console, type "Xnest :1 -ac &" and at the same console type "xterm -display :1 &" and from the popup xterm type "startkde" (or gnome-session or twm or xfdesktop ) --- Another way: from a console (ctrl+alt+f2) type "xinit /usr/X11R6/bin/xterm -- :1" (the new Windon Manager will run on ctrl+alt+f8)
469. How to start Xnest with multiple windows?Xnest -scrns 2 :1 -ac & ; from a KDE console type: "DISPLAY=:1.0 xclock", "DISPLAY=:1.1 xeyes" : NB: if you try "xterm" you are not able to use the keyboard
470. Howto troubleshoot a problem that I can not find here?Read the log (output on the screen (use: command >& log) or at /var/log) at least 5 times, find some keywords in the log: 1) use apropos <keyword> 2) think twice 3) call Miss Google at or 4) take a visit to Monsieur Newsgroup.
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473. New hints since the last release R11New hints since the last release R11
474. Some small/light applicationscurl, link2, aria2, smb4k, lighttpd
475. Mini/light X application and X serverxfce, dillo (browser), mrxvt (xterm), msttcorefonts ms truefont
476. Show "ls" as a tree like "pstree"ls -R | grep ":$" | sed -e 's/:$//' -e 's/[^-][^\/]*\//--/g' -e 's/^/ /' -e 's/-/|/'
477. How to backup a file quickly?cp /etc/ldap.conf{,.bak}
478. Some good Content Management SystemWordpress, joomla, drupal
479. Good Videoconference applicationegika (the former GnomeMeeting)
480. The Photo collates: howto print multiples images on one page?printoxx
481. A client to handle the Windows RDP (Remote Desktop Protocol) and VNC?grdc
482. How to manage multiple servers at the same time?clusterssh
483. Is there any Server Automation a la BMC BladeLogic?
484. Webcam survillence setup
485. Where to buy a micro/mini linux server?tonidoPlug, picotux, sheevaplug, nslu2, eee PC901, Jack PC, Beaglebone Black, Raspberry PI, Cubieboard, UG802, Gooseberry, apc, ODroid-X2, OLinuXino
486. Want to remotely control your home through a web box?vera from
487. How to checksum files when moving from one server to an another?md5sum <files> > output.md5 ; After moving the files, on the other server, do: md5sum -c output.md5
488. Sort 2 columns (sort the first columns and then the second column numeric)sort -k 1,1 -k 2n,4 <file>
489. How to undelete/investigate (system forensic analysis tools) my deleted harddisk?
490. How to find the serial number, the CPU speed, the Product Name, the model type?dmidecode|more
491. How to ghost/trueimage my linux?ddrescue /dev/sda1 /mnt/sda1_image.img; check the image with "mount -o loop /mnt/sda1_image.img /mnt/image"
492. How to make a USB linux boot?unetboot 2.93 (try the small distribution
493. How to buil a high performance computer cluster?, Beowulf cluster,
494. How to access a web server when the http port is closed in firewall? (assuming the ssh port is opened in FW; using ssh tunnel)from my PC: ssh -f -N -L 5000: my_account@ ; so after ssh to the web server, its http port 80 will forward (-L) to port 5000 on the PC I initiate the ssh connection. The URL will be http://localhost:5000
495. How to access a web server I can not connect directly to (using ssh tunnel)?from my PC: ssh -TNn -L 5000: my_account@ ; I connect to the web server through the ssh server (In other word when a connection is made to port 5000 localhost, the connection is forwarded through to port 80). On my PC the URL will be http://localhost:5000
496. How to setup Paltalk in Linux?Clicking here

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Copenhagen, Tuan Nguyen
Konqueror @800x600
Recompiled Mon., Mar 17, 2014