All commands (14,187)

  • make password randomly, default 8 char


    -1
    genpass() { local h x y;h=${1:-8};x=( {a..z} {A..Z} {0..9} );y=$(echo ${x[@]} | tr ' ' '\n' | shuf -n$h | xargs);echo -e "${y// /}"; }
    twfcc · 2009-10-24 04:05:42 4
  • Use multiple patterns with grep -v. So you can print all lines in a file except those containing the multiple patterns you specify.


    16
    grep 'test' somefile | grep -vE '(error|critical|warning)'
    zlemini · 2009-10-23 23:21:36 12
  • Alternative to the ping check if your firewall blocks ping. Uses curl to get the landing page silently, or fail with an error code. You can probably do this with wget as well. Show Sample Output


    2
    curl -fs brandx.jp.sme 2&>1 > /dev/null || echo brandx.jp.sme ping failed | mail -ne -s'Server unavailable' joker@jp.co.uk
    mccalni · 2009-10-23 14:29:06 4
  • Strip my code to: wmctrl -o 0,0 # autorotates to the first face. In fact [0-1279],0 wmctrl - 1280,0 # goes to the second face wmctrl -o 2560,0 # goes to the third face, and so on. # Use multiples of the horizontal display resolution. My example work for 1280x800 display, been 1280 the number of interest. Tweak the number, try a biiiig one and see your cube spinning... I put a complex example to show how fun things can be, even for my ademco and paradox alarm central network advisor interface xpto etc. It rotates two faces, print the alarm message, and goes back tho where it was. Tested on BIGLINUX 4.2, equivalent to ubuntu LTS hardy. Do not forget to activate 3D efects ( compiz cube ) Show Sample Output


    5
    wmctrl -o 2560,0 ;sleep 2 ; echo "FIRE 001" | osd_cat -o 470 -s 8 -c red -d 10 -f -*-bitstream\ vera\ sans-*-*-*--250-*-*-*-*-*-*-* ; sleep 1; wmctrl -o 0,0
    m33600 · 2009-10-23 10:00:51 17
  • already described on the other two versions, this one uses ascii characters on game style to display elapsed time. Show Sample Output


    0
    export I=$(date +%s); watch -t -n 1 'T=$(date +%s);E=$(($T-$I));hours=$((E / 3600)) ; seconds=$((E % 3600)) ; minutes=$((seconds / 60)) ; seconds=$((seconds % 60)) ; echo $(printf "%02d:%02d:%02d" $hours $minutes $seconds) | toilet -f shadow'
    m33600 · 2009-10-23 07:56:30 10
  • Variation of the theme, this one blinks in low profile on top level of X, ie, it is visible, indeed small. Try changing fonts and sizes of osd_cat


    0
    export I=$(date +%s); watch -t -n 1 'T=$(date +%s);E=$(($T-$I));hours=$((E / 3600)) ; seconds=$((E % 3600)) ; minutes=$((seconds / 60)) ; seconds=$((seconds % 60)) ; echo $(printf "%02d:%02d:%02d" $hours $minutes $seconds) | osd_cat -o 20 -d 1 -p bottom'
    m33600 · 2009-10-23 07:47:11 3
  • Works on real time clock, unix time based, decrementing the actual time from initial time saved in an environment variable exported to child process inside watch Shows elapsed time from start of script in hh:mm:ss format Non afected by system slow down due to the use of date.


    3
    export I=$(date +%s); watch -t -n 1 'T=$(date +%s);E=$(($T-$I));hours=$((E / 3600)) ; seconds=$((E % 3600)) ; minutes=$((seconds / 60)) ; seconds=$((seconds % 60)) ; echo $(printf "%02d:%02d:%02d" $hours $minutes $seconds)'
    m33600 · 2009-10-23 07:31:44 8
  • simple function , floating point number is supported.


    12
    calc(){ awk "BEGIN{ print $* }" ;}
    twfcc · 2009-10-23 06:03:07 52
  • My firefox overheats my cpu, sometimes above 90 degrees Celsius ( hence the name? ) To keep an eye on temperature, I put this command inside KAlarm ( a kind of cron) to be repeated every minute, for 5 seconds, color red ( default for osd_cat). Its pretty, ultra small, displays a micro 2 lines text on every desktop and over everything and do not steal focus or interrupt any task. I get the information passively, in the low profile bottom of the screen. Of course you can use it inside a terminal. Just do it: watch -n 60 'acpi -t | osd_cat -p bottom'


    2
    acpi -t | osd_cat -p bottom
    m33600 · 2009-10-23 05:22:01 3
  • Usefull as a light blink to remember events, mails, intrusions, etc... yet another output Since nobody ever uses the scroll lock function... Usefull to interface a linux system with some hardware, for example, opto interfacing the keyboard led to a relay to remotely reset, etc. ( a simple LDR glued over the LED will do the trick ) xset led 3 turns on the third led, ie, Scroll lock xset -led 3 turns it off xset led 1 turns on Numerical Lock led ( doesn t work on all computer ) xset led 2 turns on Caps Lock led ( idem ) Using it as a reset watchdog, the relay expected light pulses. Shall the computer hangs, the relay releases and reset the machine ( discharge of a capacitor ) ;-)


    5
    xset led 3
    m33600 · 2009-10-23 00:25:56 15
  • If you omit the function name, the command will display all definitions Show Sample Output


    5
    declare -f [ function_name ]
    haivu · 2009-10-22 17:52:47 6
  • If you issue the "set" command, you'll see a list of variables and functions. This command displays just those functions' names. Show Sample Output


    1
    set | fgrep " ()"
    haivu · 2009-10-22 17:48:54 6
  • Handled all within awk. Takes the value from $PWD and constructs directory structures and runs commands against them. The gsub() call is not necessary, but added for better visibility. If a variable DIR is given on the awk command-line, then that directory is used instead: awk -vDIR=$HOME/.ssh 'BEGIN{dir=DIR?...}' Show Sample Output


    -1
    awk 'BEGIN{dir=DIR?DIR:ENVIRON["PWD"];l=split(dir,parts,"/");last="";for(i=1;i<l+1;i++){d=last"/"parts[i];gsub("//","/",d);system("ls -ld \""d"\"");last=d}}'
    arcege · 2009-10-22 16:28:07 5
  • note the xargs at the end


    5
    shuf -i 1-49 | head -n6 | sort -n| xargs
    ioggstream · 2009-10-22 12:54:08 93
  • Can easily be scripted in order to show permission "tree" from any folder. Can also be formated with column -t { pushd .> /dev/null; cd /; for d in `echo $OLDPWD | sed -e 's/\// /g'`; do cd $d; echo -n "$d "; ls -ld .; done; popd >/dev/null ; } | column -t from http://www.commandlinefu.com/commands/view/3731/using-column-to-format-a-directory-listing Show Sample Output


    0
    pushd .> /dev/null; cd /; for d in `echo $OLDPWD | sed -e 's/\// /g'`; do cd $d; echo -n "$d "; ls -ld .; done; popd >/dev/null
    syladmin · 2009-10-22 12:32:11 3

  • 7
    echo $(shuf -i 1-49 | head -n6 | sort -n)
    twfcc · 2009-10-22 06:48:20 4
  • One character less...


    0
    flip -u <filenames>
    linuxmonkey · 2009-10-21 21:25:43 3
  • atime and mtime timestamps of $FILE2 is changed according to the ones of $FILE1. If $FILE2 doesn't exist is created. Show Sample Output


    2
    touch -r "$FILE1" "$FILE2"
    kobayashison · 2009-10-21 13:53:59 6

  • 0
    shopt -s dotglob
    sharfah · 2009-10-21 13:31:20 3
  • This could be added to .bashrc. Background: Linux usually saves history only on clean exit of shell. If shell ends unclean, history is lost. Also numerous terminals might confuse their history. With this variable set, history is immedeately written, accessible to all other open shells.


    2
    PROMPT_COMMAND="history -a"
    danam · 2009-10-21 12:33:25 4
  • set directly the wallpaper on windowmaker , use this command with display of imagemagick :) Show Sample Output


    1
    wmsetbg -s -u path_to_wallpaper
    eastwind · 2009-10-21 11:23:54 4
  • syntax : mencoder mf://filemask -mf option availble for mf : * w=value : the width of the output, by d?fault : autodetected * h=value : height of the output, by default : autodetected * fps=value : framerate of the output, by default : 25 * type=value : file format type input , avaible: jpeg, png, tga, sgi


    -1
    mencoder mf://image1.jpg,image2.jpg,image3.jpg -mf w=800:h=600:fps=25:type=jpeg -ovc copy -oac copy -o output.avi
    eastwind · 2009-10-21 09:17:22 3
  • syntax : mencoder mf://filemask -mf option availble for mf : * w=value : the width of the output, by d?fault : autodetected * h=value : height of the output, by default : autodetected * fps=value : framerate of the output, by default : 25 * type=value : file format type input , avaible: jpeg, png, tga, sgi Show Sample Output


    0
    mencoder mf://*.jpg -mf w=800:h=600:fps=25:type=jpeg -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o output.avi
    eastwind · 2009-10-21 09:14:04 3
  • Convert those .mov files that your digital camera makes to .avi Adjust the bitrate (-b) to get the appropriate file size. A larger bitrate produces a larger (higher quality) .avi file and smaller bitrate produces a smaller (lower quality) .avi file. Requires ffmpeg (see man page for details) (tested with canon camera MOV files) Other examples: ffmpeg -i input.mov -sameq -vcodec msmpeg4v2 -acodec pcm_u8 output.avi ffmpeg -i input.mov -b 1024k -vcodec msmpeg4v2 -acodec pcm_u8 output.avi


    1
    ffmpeg -i input.mov -b 4096k -vcodec msmpeg4v2 -acodec pcm_u8 output.avi
    oracular · 2009-10-21 05:44:31 9
  • Just one character longer than the sed version ('FNR==5' versus -n 5p). On my system, without using "exit" or "q", the awk version is over four times faster on a ~900K file using the following timing comparison: testfile="testfile"; for cmd in "awk 'FNR==20'" "sed -n '20p'"; do echo; echo $cmd; eval "$cmd $testfile"; for i in {1..3}; do time for j in {1..100}; do eval "$cmd $testfile" >/dev/null; done; done; done Adding "exit" or "q" made the difference between awk and sed negligible and produced a four-fold improvement over the awk timing without the "exit". For long files, an exit can speed things up: awk 'FNR==5{print;exit}' <file>


    2
    awk 'FNR==5' <file>
    dennisw · 2009-10-20 22:52:41 5
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Print github url for the current url
Works for repos cloned via ssh or https.

Adequately order the page numbers to print a booklet
Useful if you don't have at hand the ability to automatically create a booklet, but still want to. F is the number of pages to print. It *must* be a multiple of 4; append extra blank pages if needed. In evince, these are the steps to print it, adapted from https://help.gnome.org/users/evince/stable/duplex-npage.html.en : 1) Click File ▸ Print. 2) Choose the General tab. Under Range, choose Pages. Type the numbers of the pages in this order (this is what this one-liner does for you): n, 1, 2, n-1, n-2, 3, 4, n-3, n-4, 5, 6, n-5, n-6, 7, 8, n-7, n-8, 9, 10, n-9, n-10, 11, 12, n-11... ...until you have typed n-number of pages. 3) Choose the Page Setup tab. - Assuming a duplex printer: Under Layout, in the Two-side menu, select Short Edge (Flip). - If you can only print on one side, you have to print twice, one for the odd pages and one for the even pages. In the Pages per side option, select 2. In the Page ordering menu, select Left to right. 4) Click Print.

Protect against buffer overflow
This command solve the problem ping: sendmsg: No buffer space available to.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Test your total disk IO capacity, regardless of caching, to find out how fast the TRUE speed of your disks are
Depending on the speed of you system, amount of RAM, and amount of free disk space, you can find out practically how fast your disks really are. When it completes, take the number of MB copied, and divide by the line showing the "real" number of seconds. In the sample output, the cached value shows a write speed of 178MB/s, which is unrealistic, while the calculated value using the output and the number of seconds shows it to be more like 35MB/s, which is feasible.

locate bin, src, and man file for a command

Vi - Matching Braces, Brackets, or Parentheses
This is a simple command for jumping to the matching brace, square bracket, or parentheses. For example, it can take you from the beginning of a function to the end with one key stroke. To delete everything between the pairs of {}, [], or (), issue the command: $ d% To replace text between pairs of braces, brackets, or parentheses, issue the command: $ c% You can also use this command to find out if an opening brace has been properly closed.

list block devices
Shows all block devices in a tree with descruptions of what they are.

Check if a package is installed. If it is, the version number will be shown.
If the first two letters are "ii", then the package is installed. You can also use wildcards. For example, . $ dpkg -l openoffice* . Note that dpkg will usually not report packages which are available but uninstalled. If you want to see both which versions are installed and which versions are available, use this command instead: . $ apt-cache policy python

run remote linux desktop
First of all you need to run this command. X :12.0 vt12 2>&1 >/dev/null & This command will open a X session on 12th console. And it will show you blank screen. Now press Alt + Ctrl + F7. You will get your original screen. Now run given command "xterm -display :12.0 -e ssh -X user@remotesystem &". After this press Alt + Ctrl + F12. You will get a screen which will ask you for password for remote linux system. And after it you are done. You can open any window based application of remote system on your desktop. Press Alt + Ctrl + F7 for getting original screen.


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