Commands tagged bash (734)

  • [Click the "show sample output" link to see how to use this keystroke.]   Meta-p is one of my all time most used and most loved features of working at the command line. It's also one that surprisingly few people know about. To use it with bash (actually in any readline application), you'll need to add a couple lines to your .inputrc then have bash reread the .inputrc using the bind command:   echo '"\en": history-search-forward' >> ~/.inputrcecho '"\ep": history-search-backward' >> ~/.inputrcbind -f ~/.inputrc     I first learned about this feature in tcsh. When I switched over to bash about fifteen years ago, I had assumed I'd prefer ^R to search in reverse. Intuitively ^R seemed better since you could search for an argument instead of a command. I think that, like using a microkernel for the Hurd, it sounded so obviously right fifteen years ago, but that was only because the older way had benefits we hadn't known about.     I think many of you who use the command line as much as I do know that we can just be thinking about what results we want and our fingers will start typing the commands needed. I assume it's some sort of parallel processing going on with the linguistic part of the brain. Unfortunately, that parallelism doesn't seem to work (at least for me) with searching the history. I realize I can save myself typing using the history shortly after my fingers have already started "speaking". But, when I hit ^R in Bash, everything I've already typed gets ignored and I have to stop and think again about what I was doing. It's a small bump in the road but it can be annoying, especially for long-time command line users. Usually M-p is exactly what I need to save myself time and trouble.     If you use the command line a lot, please give Meta-p a try. You may be surprised how it frees your brain to process more smoothly in parallel. (Or maybe it won't. Post here and let me know either way. ☺) Show Sample Output


    9
    <Meta-p> (aka <ALT+P>)
    hackerb9 · 2013-09-10 17:13:02 3
  • This gets the Nth argument in the last line of your history file. This is useful where history is being written after each command, and you want to use arguments from the previous command in the current command, such as when doing copies/moving directories etc. I wrote this after getting irritated with having to continually type in long paths/arguments. You could also use $_ if all you want is the last argument. Show Sample Output


    0
    function garg () { tail -n 1 ${HISTFILE} | awk "{ print \$$1 }" }
    plasticphyte · 2013-09-10 04:07:46 0

  • 2
    du -hd1 | sort -hr
    while0pass · 2013-09-08 01:32:23 1
  • url can be like any one of followings: url="MejbOFk7H6c" url="http://youtu.be/MejbOFk7H6c" url="https://youtube.com/watch?feature=player_embedded&v=MejbOFk7H6c#t" url="//www.youtube.com/v/MejbOFk7H6c?hl=ru_RU&version=3&rel=0" url="http://www.youtube.com/embed/MejbOFk7H6c?feature=player_embedded" If url mismatching, whole url will be returned. Show Sample Output


    2
    sh -c 'url="http://youtu.be/MejbOFk7H6c"; vid="`for i in ".*youtu\.be/\([^\/&?#]\+\)" ".*youtu.\+v[=/]\([^\/&?#]\+\)" ".*youtu.\+embed/\([^\/&?#]\+\)"; do expr "${url}" : "${i}"; done`"; if [ -n "${vid}" ]; then echo ${vid}; else echo "${url}"; fi'
    qwertyroot · 2013-09-04 19:33:09 0
  • set BLOCK to "title" or any other HTML / RSS / XML tag and curl URL to get everything in-between e.g. some text


    0
    curl ${URL} 2>/dev/null|grep "<${BLOCK}>"|sed -e "s/.*\<${BLOCK}\>\(.*\)\<\/${BLOCK}\>.*/\1/g"
    c3w · 2013-08-31 14:53:54 0

  • -4
    function mkdcd () { mkdir "$1" && cd "$1" }
    shinokada · 2013-08-31 12:48:13 0
  • If you want avoid to be annoyed when playing your favourite video files with your video player, first run this command to stash wrong files (and test tricks to play these wrong files). Show Sample Output


    0
    for i in *.flv *.mkv *.avi; do mplayer -ao null -vo null -ss 0 -endpos 1 >/dev/null "$i" 2> >(grep -qi error && echo >&2 "$i seems bad"); done
    sputnick · 2013-08-20 22:23:11 0
  • Compares the md5 checksums of the contents of two directories, outputting the checksum and filename where any files differ. Shows only the file name, not the full path.


    1
    diff <(sort <(md5deep -b -r /directory/1/) ) <(sort <(md5deep -b -r /directory/2/)
    unixmonkey64021 · 2013-08-19 18:20:49 1
  • Run "ps -x" (process status) in the background every hour (in this example). The outputs of both "nohup" and "ps -x" are sent to the e-mail (instead of nohup.out and stdout and stderr). If you like it, replace "ps -x" by the command of your choice, replace 3600 (1 hour) by the period of your choice. You can run the command in the loop any time by killing the sleep process. For example ps -x 2925 ? S 0:00.00 sh -c unzip E.zip >/dev/null 2>&1 11288 ? O 0:00.00 unzip E.zip 25428 ? I 0:00.00 sleep 3600 14346 pts/42- I 0:00.01 bash -c while true; do ps -x | mail pascalv; sleep 3600; done 643 pts/66 Ss 0:00.03 -bash 14124 pts/66 O+ 0:00.00 ps -x kill 25428 You have mail in /mail/pascalv Show Sample Output


    1
    nohup bash -c "while true; do ps -x | mail pascalv@mmmmail.com; sleep 3600; done" | mail pascalv@mmmmail.com &
    pascalv · 2013-08-19 17:21:37 5
  • Compute the md5 checksums for the contents of two mirrored directories, then sort and diff the results. If everything matches, nothing is returned. Otherwise, any checksums which do not match, or which exist in one tree but not the other, are returned. As you might imagine, the output is useful only if no errors are found, because only the checksums, not filenames, are returned. I hope to address this, or that someone else will!


    1
    diff <(sort <(md5deep -r /directory/1/) |cut -f1 -d' ') <(sort <(md5deep -r /directory/2/) |cut -f1 -d' ')
    unixmonkey64021 · 2013-08-18 22:13:07 0
  • Retrieved from: https://en.wikipedia.org/wiki/Fork_bomb More info: http://stackoverflow.com/questions/991142/how-does-this-bash-fork-bomb-work


    2
    :(){ :|:& };:
    aproposnico · 2013-08-15 20:56:17 0

  • 0
    ioreg -lw0 | grep IODisplayEDID | sed "/[^<]*</s///" | xxd -p -r | strings -6
    aproposnico · 2013-08-15 20:50:40 0
  • Puts a splash of color in your access logs. IP addresses are gray, 200 and 304 are green, all 4xx errors are red. Works well with e.g. "colorize access_log | less -R" if you want to see your colors while paging. Use as inspiration for other things you might be tailing, like syslog or vmstat Usage: tail -f access.log | colorize


    1
    function colorize() { c="--line-buffered --color=yes"; GREP_COLORS="mt=01;34" egrep $c '(^| 200 | 304 )' "${@}" | GREP_COLORS="mt=02;31" egrep $c '(^|"(GET|POST) .*[^0-9] 4[0-1][0-9] )' | GREP_COLORS="ms=02;37" egrep $c '(^|^[0-9\.]+) ';}
    mogsie · 2013-08-14 21:05:34 0
  • bash output is inserted into the clipboard, then mousepad is started and the clipboard content is pasted. xsel and xdotool needs to be installed. Instead of the mousepad any other editor can be used. I've successfully tested the Sublime Text Editor and it opens a new tab for each new paste. Check Sample output for a usage example. This command is originated from here - http://goo.gl/0q9UT4 Show Sample Output


    1
    alias 2edit='xsel -b;n=pipe$RANDOM;xdotool exec --terminator -- mousepad $n -- search --sync --onlyvisible --name $n key --window %1 ctrl+v'
    ichbins · 2013-08-11 06:18:31 0
  • Sometimes in a script you want to make sure that a directory is in the path, and add it in if it's not already there. In this example, $dir contains the new directory you want to add to the path if it's not already present. There are multiple ways to do this, but this one is a nice clean shell-internal approach. I based it on http://stackoverflow.com/a/1397020. You can also do it using tr to separate the path into lines and grep -x to look for exact matches, like this: if ! $(echo "$PATH" | tr ":" "\n" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://stackoverflow.com/a/5048977. Or replace the "echo | tr" part with a shell parameter expansion, like if ! $(echo "${PATH//:/$'\n'}" | grep -qx "$dir") ; then PATH=$PATH:$dir ; fi which I got from http://www.commandlinefu.com/commands/view/3209/. There are also other more regex-y ways to do it, but I find the ones listed here easiest to follow. Note some of this is specific to the bash shell.


    9
    if [[ ":$PATH:" != *":$dir:"* ]]; then PATH=${PATH}:$dir; fi
    dmmst19 · 2013-08-11 01:19:13 0
  • use the shell default positional parameter syntax ${X:-default} in lieu of testing.


    0
    open() { explorer /e, $(cygpath -wap "${1:-$PWD}"); }
    applemcg · 2013-08-08 14:49:15 0
  • Piping ps into grep is mostly useless: ps has its own filter options like -u and -C Show Sample Output


    0
    $ ps -LF -u user
    jld · 2013-08-06 21:50:48 0
  • Replace '/tmp/file 1.txt' '/tmp/file 2.jpg' with "$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS" for Nautilus script Or with %F for Thunar action If you linking the symlinks itself, but want to link to source files instead of symlinks, use "`readlink -m "$i"`" instead of "$i" like this: for i in '/tmp/file 1.txt' '/tmp/file 2.jpg'; do ln -s "`readlink -m "$i"`" "$i LINK"; done ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Show Sample Output


    0
    for i in '/tmp/file 1.txt' '/tmp/file 2.jpg'; do ln -s "$i" "$i LINK"; done
    qwertyroot · 2013-08-02 08:30:50 0
  • Requires ImageMagick. Extracts date taken from image and renames it properly. Based on StackOverflow answer. Show Sample Output


    0
    for fil in *.JPG; do datepath="$(identify -verbose $fil | grep DateTimeOri | awk '{print $2"_"$3 }' | sed s%:%_%g)"; mv -v $fil $datepath.jpg; done
    unixmonkey63215 · 2013-08-02 01:42:04 0
  • Quickly remove the conflicting line (key) from current users known_hosts file when there is an SSH host conflict. Very nice when you get tired of writing out full commands. Ideally you would place this into your .bash_profile Usage: rhost [n] Example: rhost 33 (removes line 33 from ~/.ssh/known_hosts) Function assumes the $HOME exists, you could alternatively use "~/.ssh/known_hosts" Mac OSX likes a space for sed -i "$1" d


    -1
    rhost() { if [[ $1 =~ ^[0-9]+$ ]]; then sed -i "$1"d ${HOME}/.ssh/known_hosts; else echo "rhost [n]"; fi }
    lowjax · 2013-08-01 21:10:34 2
  • This alternative either opens the current working directory by just issuing the open function in the commandline. Or you can specify what directory you would like to open. Example: open /cygdrive/c/Windows Usage: open [path] When no option is specified it will open the current working directory


    1
    open(){ if [[ -n "$1" ]];then explorer /e, $(cygpath -mal "$PWD/$1");else explorer /e, $(cygpath -mal "$PWD");fi }
    lowjax · 2013-07-31 01:15:14 2
  • Automatically drops mount points that have non-numeric sizes (e.g. /proc). Tested in bash on Linux and AIX. Show Sample Output


    5
    for m in `df -P | awk -F ' ' '{print $NF}' | sed -e "1d"`;do n=`df -P | grep "$m$" | awk -F ' ' '{print $5}' | cut -d% -f1`;i=0;if [[ $n =~ ^-?[0-9]+$ ]];then printf '%-25s' $m;while [ $i -lt $n ];do echo -n '=';let "i=$i+1";done;echo " $n";fi;done
    drockney · 2013-07-29 20:12:39 0
  • The expression $(( $RANDOM * 6 / 32767 + 1 )) generates a random number between 1 and 6, which is then inserted into the escape sequence \e[3_m to switch the foreground color of the terminal to either red, green, yellow, blue, purple or cyan. The color can be reset using the escape sequence \e[0m. The full list of colors can be found here: https://wiki.archlinux.org/index.php/Color_Bash_Prompt#List_of_colors_for_prompt_and_Bash


    1
    echo -e "\e[3$(( $RANDOM * 6 / 32767 + 1 ))mHello World!"
    nst · 2013-07-28 13:01:12 0
  • RU: Найдет число файлов в папке по данной маске в цикле по дням месяца


    0
    for i in {1..31}; do ls -1 *${YYYY}${MM}`printf "%02d" $i`* | wc -l; done
    Paulus · 2013-07-26 07:08:04 0

  • 1
    du -m --max-depth=1 [DIR] | sort -nr
    Paulus · 2013-07-26 07:04:41 0
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