Commands tagged bash (821)

  • Thanks for the submit! My alternative produces summaries only for directories. The original post additionally lists all files in the current directory. Sometimes the files, they just clutter up the output. Once the big directory is located, *then* worry about which file(s) are consuming so much space.


    -1
    du -kd | egrep -v "/.*/" | sort -n
    rmbjr60 · 2010-03-30 15:40:35 3
  • The shell has perfectly adequate pattern matching for simple expressions. Show Sample Output


    -1
    function ends_in_y() { case $(date +%A) in *y ) true ;; * ) false ;; esac } ; ends_in_y && echo ok
    unixmonkey9199 · 2010-04-06 22:18:52 3
  • Essentially the same as funky's alias, but will not traverse filesystems and has nicer formatting. Show Sample Output


    -1
    alias dush="du -xsm * | sort -n | awk '{ printf(\"%4s MB ./\",\$1) ; for (i=1;i<=NF;i++) { if (i>1) printf(\"%s \",\$i) } ; printf(\"\n\") }' | tail"
    dopeman · 2010-07-15 10:38:27 4
  • forces user to rw, group to r, and other to no access. files will not be marked executable. directories will be executable for users and groups only. Show Sample Output


    -1
    chmod -R u=rw-x+X,g=r-x+X,o= .
    donnoman · 2010-07-16 18:42:00 5
  • Output the html from xkcd's index.html, filter out the html tags, and then view it in gwenview. Show Sample Output


    -1
    gwenview `wget -O - http://xkcd.com/ | grep 'png' | grep '<img src="http://imgs.xkcd.com/comics/' | sed s/title=\".*//g | sed 's/.png\"/.png/g' | sed 's/<img src=\"//g'`
    hunterm · 2010-08-24 22:21:51 4
  • Shorter version with curl and awk


    -1
    eog `curl 'http://xkcd.com/' | awk -F "ng): |</h" '/embedding/{print $2}'`
    dog · 2010-08-25 14:04:30 3
  • It works in every linux box Show Sample Output


    -1
    cat /proc/cpuinfo
    magicjohnson_ · 2010-09-24 09:27:58 3
  • The command was too long for the command box, so here it is: echo $(( `wget -qO - http://i18n.counter.li.org/ | grep 'users registered' | sed 's/.*\<font size=7\>//g' | tr '\>' ' ' | sed 's/<br.*//g' | tr ' ' '\0'` + `curl --silent http://www.dudalibre.com/gnulinuxcounter?lang=en | grep users | head -2 | tail -1 | sed 's/.*<strong>//g' | sed 's/<\/strong>.*//g'` )) This took me about an hour to do. It uses wget and curl because, dudalibre.com blocks wget, and wget worked nicely for me. Show Sample Output


    -1
    Check the Description below.
    hunterm · 2010-10-07 04:22:32 3
  • Often times you run a command in the terminal and you don't realize it's going to take forever. You can open a new terminal, but you lose the local history of the suspended one. You can stop the running command using , but that may produce undesirable side-effects. suspends the job, and (assuming you have no other jobs running in the background) %1 resumes it. Appending & tells it to run in the background. You now have a job running concurrently with your terminal. Note this will still print any output to the same terminal you're working on. Tested on zsh and bash. Show Sample Output


    -1
    <ctrl+z> %1 &
    joem86 · 2010-10-25 17:43:38 5
  • Just added view with the eog viewer.


    -1
    wget -O xkcd_$(date +%y-%m-%d).png `lynx --dump http://xkcd.com/|grep png`; eog xkcd_$(date +%y-%m-%d).png
    theanalyst · 2010-10-27 13:42:55 3
  • Uses xargs to call the second grep with the first grep's results as arguments


    -1
    grep -l bar *.log | xargs grep -l foo
    dlebauer · 2011-01-10 19:54:46 3
  • This will tighten up security for your box. The default value for PermitRootLogin sadly is 'yes'.


    -1
    s=/etc/ssh/sshd_config;r=PermitRootLogin;cp $s{,.old}&& if grep $r $s;then sed "s/$r yes/$r no/" $s.old > $s; else echo $r no >> $s;fi
    kzh · 2011-01-30 23:41:59 11
  • Here's a bash version using an array.


    -1
    a=(*); echo ${a[$((RANDOM % ${#a[@]}))]}
    putnamhill · 2011-03-18 13:24:52 3
  • Sometimes you might need to have two copies of data that is in tar. You might unpack, and then copy, but if IO is slow, you might lower it by automatically writing it twice (or more times)


    -1
    mkdir copy{1,2}; gzip -dc file.tar.gz | tee >( tar x -C copy1/ ) | tar x -C copy2/
    depesz · 2011-04-14 17:02:05 5

  • -1
    echo $(( $( date +%s ) - $( stat -c %Y * | sort -nr | head -n 1 ) ))
    depesz · 2011-05-12 14:29:45 3
  • urldecode files in current directrory


    -1
    ls * | while read fin;do fout=$(echo -n $fin | sed -e's/%\([0-9A-F][0-9A-F]\)/\\\\\x\1/g' | xargs echo -e);if [ "$fout" != "$fin" ];then echo "mv '$fin' '$fout'";fi;done | bash -x
    pawelb1973 · 2011-05-18 07:24:54 82
  • Newer versions of Dropbox let you choose the location for your Dropbox folder. If you use script to put things into your Dropbox folder (todo list, screenshots, torrents etc.) but have the Dropbox folder in different locations on your other computers this lets you use the same script on all systems without having to tell it where the Dropbox folder is. Show Sample Output


    -1
    sqlite3 $HOME/.dropbox/config.db "select value from config where key like '%dropbox_path%'"
    mobilediesel · 2011-06-05 08:26:02 13
  • Outputs the real time it takes a Redis ping to run in thousands of a second without any proceeding 0's. Useful for logging or scripted action.


    -1
    TIME=$( { time redis-cli PING; } 2>&1 ) ; echo $TIME | awk '{print $3}' | sed 's/0m//; s/\.//; s/s//; s/^0.[^[1-9]*//g;'
    allrightname · 2011-08-11 19:09:49 4

  • -1
    RANGE=`wc -l /usr/share/dict/words | sed 's/^\([0-9]*\) .*$/\1/'`; for i in {1..4}; do let "N = $RANDOM % $RANGE"; sed -n -e "${N}p" /usr/share/dict/words | tr -d '\n'; done; RANGE=100; let "N = $RANDOM % $RANGE"; echo $N
    unixmonkey24597 · 2011-08-16 07:04:57 3
  • uses fifo and sets to a specific port. In this case 4201.


    -1
    mkfifo ._b; nc -lk 4201 0<._b | /bin/bash &>._b;
    gt · 2011-08-21 05:22:41 3
  • This is an "argument calculator" funktion. The precision is set to 4 and you can use dot (.) or comma (,) as decimal mark (which is great for german users with a comma on the numpad).


    -1
    calc() { echo "scale=4; ${*//,/.}" | bc -l; }
    fpunktk · 2011-10-24 19:58:20 4
  • Schematics: command [options] [paste your variable here] parameter command [options] [paste entire column of variables here] parameter ... (hard-code command "c" and parameter "e" according to your wishes: in example shown command = "cp -a" and parameter = "~") Features: - Quick exchange only variable part of a long command line - Make variable part to be an entire column of data (i.e. file list) - Full control while processing every single item Hints: Paste column of data from anywhere. I.e. utilize the Block Select Mode to drag, select and copy columns (In KDE Konsole with Ctrl+Alt pressed, or only Ctrl pressed in GNOME Terminal respectively). Disadvantages: You can paste only one single variable in a row. If there are more space separated variables in a row only first one will be processed, but you can arrange your variables in a column instead. To transpose rows to columns or vice versa look at Linux manual pages for 'cut' and 'paste'. TODO: - add edit mode to vary command "c" and parameter "e" on the fly - add one edit mode more to handle every list item different - add y/n/a (=All) instead of only y(=default)/n to allowed answers Disclaimer: The code is not optimized, only the basic idea is presented here. It's up to you to shorten code or extend the functionality. Show Sample Output


    -1
    c="cp -a";e="~";echo -e "\npaste\n";i=0;k="1"; while [[ "$k" != "" ]]; do read -a k;r[i]=$k;((i++));done;i=0;while :;do t=${r[i]};[ "$t" == "" ] && break; g=$(echo $c ${r[i]} $e);echo -e $g "\ny/n?";read y;[ "$y" != "n" ] && eval $g;((i++));done
    knoppix5 · 2011-12-04 12:45:44 4
  • Mac install ssh-copy-id From there on out, you would upload keys to a server like this: (make sure to double quote the full path to your key) ssh-copy-id -i "/PATH/TO/YOUR/PRIVATE/KEY" username@server or, if your SSH server uses a different port (often, they will require that the port be '2222' or some other nonsense: (note the double quotes on *both* the "/path/to/key" and "user@server -pXXXX"): ssh-copy-id -i "/PATH/TO/YOUR/PRIVATE/KEY" "username@server -pXXXX" ...where XXXX is the ssh port on that server


    -1
    sudo curl "http://hg.mindrot.org/openssh/raw-file/c746d1a70cfa/contrib/ssh-copy-id" -o /usr/bin/ssh-copy-id && sudo chmod 755 /usr/bin/ssh-copy-id
    misterich · 2012-02-09 20:29:24 5
  • You need to have mtr installed on your host.


    -1
    mtr google.com
    d_voge · 2012-02-19 22:27:48 3
  • tail() { thbin="/usr/bin/tail"; if [ "${1:0:1}" != "-" ]; then fc=$(($#==0?1:$#)); lpf="$((($LINES - 3 - 2 * $fc) / $fc))"; lpf="$(($lpf<1?2:$lpf))"; [ $fc -eq 1 ] && $thbin -n $lpf "$@" | /usr/bin/fold -w $COLUMNS | $thbin -n $lpf || $thbin -n $lpf "$@"; else $thbin "$@"; fi; unset lpf fc thbin; } This is a function that implements an improved version of tail. It tries to limit the number of lines so that the screen is filled completely. It works with pipes, single and multiple files. If you add different options to tail, they will overwrite the settings from the function. It doesn't work very well when too many files (with wrapped lines) are specified. Its optimised for my three-line prompt. It also works for head. Just s/tail/head/g Don't set 'thbin="tail"', this might lead to a forkbomb.


    -1
    tail() { thbin="/usr/bin/tail"; if [ "${1:0:1}" != "-" ]; then fc=$(($#==0?1:$#)); lpf="$((($LINES - 3 - 2 * $fc) / $fc))"; lpf="$(($lpf<1?2:$lpf))"; [ $fc -eq 1 ] && $thbin -n $lpf "$@" | /usr/bin/fold -w $COLUMNS | $thbin -n $lpf || $thbin -n $lpf...
    fpunktk · 2012-03-23 19:00:30 3
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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"

cpuinfo

Advanced python tracing
Trace python statement execution and syscalls invoked during that simultaneously

floating point operations in shell scripts
allows you to use floating point operations in shell scripts

Given process ID print its environment variables
Same as previous but without fugly sed =x

Double your disk read performance in a single command
(WARN) This will absolutely not work on all systems, unless you're running large, high speed, hardware RAID arrays. For example, systems using Dell PERC 5/i SAS/SATA arrays. If you have a hardware RAID array, try it. It certainly wont hurt. You may be can test the speed disk with some large file in your system, before and after using this: $ time dd if=/tmp/disk.iso of=/dev/null bs=256k To know the value of block device parameter known as readahead. $ blockdev --getra /dev/sdb And set the a value 1024, 2048, 4096, 8192, and maybe 16384... it really depends on the number of hard disks, their speed, your RAID controller, etc. (see sample)

Shell function to create a menu of items which may be inserted into the X paste buffer.
The function will take a comma separated list of items to be 'selected' by xsel -i: $ smenu "First item to paste,Paste me #2,Third menu item" You will then be prompted to choose one of the menu items. After you choose, you will be able to paste the string by clicking the middle mouse button. The menu will keep prompting you to choose menu items until you break out with Control-C.

Make changes in any profile available immediately/Change to default group
Changes your group to the default group, has the same effect as sourcing your profile/rc file (in any shell) or logging out and back in again.

FAST Search and Replace for Strings in all Files in Directory
I needed a way to search all files in a web directory that contained a certain string, and replace that string with another string. In the example, I am searching for "askapache" and replacing that string with "htaccess". I wanted this to happen as a cron job, and it was important that this happened as fast as possible while at the same time not hogging the CPU since the machine is a server. So this script uses the nice command to run the sh shell with the command, which makes the whole thing run with priority 19, meaning it won't hog CPU processing. And the -P5 option to the xargs command means it will run 5 separate grep and sed processes simultaneously, so this is much much faster than running a single grep or sed. You may want to do -P0 which is unlimited if you aren't worried about too many processes or if you don't have to deal with process killers in the bg. Also, the -m1 command to grep means stop grepping this file for matches after the first match, which also saves time.

exit if another instance is running


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