Commands tagged bash (821)

  • Example : vim /etc/fstab ## damn <ctrl+u> sudo <ctrl+y> ## like a boss. Example 2 : sudo vim /root/bin/ ##uh... autocomplete doesn't work... <ctrl+u> sudo ls /root/bin ##ah! that's the name of the file! <ctrl+y> sudo vim /root/bin/ ##resume here! Thanks readline!


    223
    <ctrl+u> [...] <ctrl+y>
    adeverteuil · 2010-07-23 03:33:46 34

  • 147
    disown -a && exit
    prayer · 2009-04-10 12:22:34 33
  • When using reverse-i-search you have to type some part of the command that you want to retrieve. However, if the command is very complex it might be difficult to recall the parts that will uniquely identify this command. Using the above trick it's possible to label your commands and access them easily by pressing ^R and typing the label (should be short and descriptive). UPDATE: One might suggest using aliases. But in that case it would be difficult to change some parts of the command (such as options, file/directory names, etc).


    100
    some_very_long_and_complex_command # label
    jamolkhon · 2009-09-08 05:58:27 30

  • 99
    lsof -P -i -n
    OJM · 2009-09-19 18:28:48 33
  • CDPATH tells the cd command to look in this colon-separated list of directories for your destination. My preferred order are 1) the current directory, specified by the empty string between the = and the first colon, 2) the parent directory (so that I can cd lib instead of cd ../lib), 3) my home directory, and 4) my ~/projects directory.


    88
    CDPATH=:..:~:~/projects
    haivu · 2009-03-20 14:50:25 23
  • /usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.google.com/ then !:- http://www.commandlinefu.com/ is the same as /usr/sbin/ab2 -f TLS1 -S -n 1000 -c 100 -t 2 http://www.commandlinefu.com/


    78
    !:-
    new_user · 2010-05-15 15:12:47 18
  • The biggest advantage of this over the functions is that it is portable.


    60
    mkdir /home/foo/doc/bar && cd $_
    kzh · 2011-08-12 11:29:19 15
  • This is the result of a several week venture without X. I found myself totally happy without X (and by extension without flash) and was able to do just about anything but watch YouTube videos... so this a the solution I came up with for that. I am sure this can be done better but this does indeed work... and tends to work far better than YouTube's ghetto proprietary flash player ;-) Replace $i with any YouTube ID you want and this will scrape the site for the _real_ URL to the full quality .FLV file on Youtube's server and will then will hand that over to mplayer (or vlc or whatever you want) to be streamed. In some browsers you can replace $i with just a % or put this in a shell script so all YouTube IDs can be handed directly off to your media player of choice for true streaming without the need for Flash or a downloader like clive. (I do however fully recommend clive if you wish to archive videos instead of streaming them) If any interest is shown I would be more than happy to provide similar commands for other sites. Most streaming flash players use similar logic to YouTube. Edit: 05/03/2011 - Updated line to work with current YouTube. It could be a lot prettier but I will probably follow up with another update when I figure out how to get rid of that pesky Grep. Sed should take that syntax... but it doesn't. Original (no longer working) command: mplayer -fs $(echo "http://youtube.com/get_video.php?$(curl -s $youtube_url | sed -n "/watch_fullscreen/s;.*\(video_id.\+\)&title.*;\1;p")") Show Sample Output


    58
    i="8uyxVmdaJ-w";mplayer -fs $(curl -s "http://www.youtube.com/get_video_info?&video_id=$i" | echo -e $(sed 's/%/\\x/g;s/.*\(v[0-9]\.lscache.*\)/http:\/\/\1/g') | grep -oP '^[^|,]*')
    lrvick · 2009-03-09 03:57:44 53
  • defines a handy function for quick calculations from cli. once defined: ? 10*2+3 Show Sample Output


    58
    ? () { echo "$*" | bc -l; }
    fizz · 2009-06-28 20:15:30 27
  • This version uses read instead of eval.


    57
    read day month year <<< $(date +'%d %m %y')
    putnamhill · 2011-07-29 15:05:19 23
  • You're running a script, command, whatever.. You don't expect it to take long, now 5pm has rolled around and you're ready to go home... Wait, it's still running... You forgot to nohup it before running it... Suspend it, send it to the background, then disown it... The ouput wont go anywhere, but at least the command will still run... Show Sample Output


    53
    ^Z $bg $disown
    fall0ut · 2009-03-17 21:52:52 27
  • for one line per process: ss -p | cat for established sockets only: ss -p | grep STA for just process names: ss -p | cut -f2 -sd\" or ss -p | grep STA | cut -f2 -d\"


    52
    ss -p
    Escher · 2009-09-19 21:55:01 14
  • This is how I typically grep. -R recurse into subdirectories, -n show line numbers of matches, -i ignore case, -s suppress "doesn't exist" and "can't read" messages, -I ignore binary files (technically, process them as having no matches, important for showing inverted results with -v) I have grep aliased to "grep --color=auto" as well, but that's a matter of formatting not function.


    49
    grep -RnisI <pattern> *
    birnam · 2009-09-22 15:09:43 31
  • Same as http://www.commandlinefu.com/commands/view/5876, but for bash. This will show a numerical value for each of the 256 colors in bash. Everything in the command is a bash builtin, so it should run on any platform where bash is installed. Prints one color per line. If someone is interested in formatting the output, paste the alternative.


    49
    for code in {0..255}; do echo -e "\e[38;05;${code}m $code: Test"; done
    scribe · 2010-06-19 02:14:42 14
  • This command shows the various shortcuts that can be use in bash, including Ctrl+L, Ctrl+R, etc... You can translate "\C-y" to Ctrl+y, for example. Show Sample Output


    43
    bind -P
    ricardofunke · 2012-05-28 18:51:59 16
  • This uses Bash's "process substitution" feature to compare (using diff) the output of two different process pipelines.


    35
    diff <(cd dir1 && find | sort) <(cd dir2 && find | sort)
    mbirk · 2009-05-21 04:44:29 45
  • show only the name of the apps that are using internet Show Sample Output


    35
    lsof -P -i -n | cut -f 1 -d " "| uniq | tail -n +2
    edo · 2009-09-19 21:23:54 25
  • How often do you make a directory (or series of directories) and then change into it to do whatever? 99% of the time that is what I do. This BASH function 'md' will make the directory path then immediately change to the new directory. By using the 'mkdir -p' switch, the intermediate directories are created as well if they do not exist. Show Sample Output


    32
    md () { mkdir -p "$@" && cd "$@"; }
    drewk · 2009-09-24 16:09:19 20
  • If you're a moron like me, sometimes your fingers get away from you and you, for example, enter your password when you're already authenticated to ssh-agent, sudo, etc., and your password ends up in shell history. Here's how to get it out. Show Sample Output


    31
    history -d
    sud0er · 2009-04-27 20:19:09 19
  • sorts the files by integer megabytes, which should be enough to (interactively) find the space wasters. Now you can dush for the above output, dush -n 3 for only the 3 biggest files and so on. It's always a good idea to have this line in your .profile or .bashrc Show Sample Output


    29
    alias dush="du -sm *|sort -n|tail"
    funky · 2010-03-26 10:18:57 15
  • Run the alias command, then issue ps aux | head and resize your terminal window (putty/console/hyperterm/xterm/etc) then issue the same command and you'll understand. ${LINES:-`tput lines 2>/dev/null||echo -n 12`} Insructs the shell that if LINES is not set or null to use the output from `tput lines` ( ncurses based terminal access ) to get the number of lines in your terminal. But furthermore, in case that doesn't work either, it will default to using the deafault of 12 (-2 = 10). The default for HEAD is to output the first 10 lines, this alias changes the default to output the first x lines instead, where x is the number of lines currently displayed on your terminal - 2. The -2 is there so that the top line displayed is the command you ran that used HEAD, ie the prompt. Depending on whether your PS1 and/or PROMPT_COMMAND output more than 1 line (mine is 3) you will want to increase from -2. So with my prompt being the following, I need -7, or - 5 if I only want to display the commandline at the top. ( https://www.askapache.com/linux/bash-power-prompt/ ) 275MB/748MB [7995:7993 - 0:186] 06:26:49 Thu Apr 08 [askapache@n1-backbone5:/dev/pts/0 +1] ~ In most shells the LINES variable is created automatically at login and updated when the terminal is resized (28 linux, 23/20 others for SIGWINCH) to contain the number of vertical lines that can fit in your terminal window. Because the alias doesn't hard-code the current LINES but relys on the $LINES variable, this is a dynamic alias that will always work on a tty device. Show Sample Output


    27
    alias head='head -n $((${LINES:-`tput lines 2>/dev/null||echo -n 12`} - 2))'
    AskApache · 2010-04-08 22:37:06 14
  • You can use [n]> combined with >(cmd) to attach the various output file descriptors to be the input of different commands.


    26
    some_command > >(/bin/cmd_for_stdout) 2> >(/bin/cmd_for_stderr)
    tylerl · 2009-12-01 03:58:04 6
  • Uses the last argument of the last executed command, and gets the directory name from it. Use $!:t for the filename alone, without the dirname. Show Sample Output


    25
    cd !$:h
    lingo · 2009-08-07 00:37:08 10
  • Add this to a fiend's .bashrc. PROMPT_COMMAND will run just before a prompt is drawn. RANDOM will be between 0 and 32768; in this case, it'll run about 1/10th of the time. \033 is the escape character. I'll call it \e for short. \e7 -- save cursor position. \e[%d;%dH -- move cursor to absolute position \e[4%dm \e[m -- draw a random color at that point \e8 -- restore position.


    25
    PROMPT_COMMAND='if [ $RANDOM -le 3200 ]; then printf "\0337\033[%d;%dH\033[4%dm \033[m\0338" $((RANDOM%LINES+1)) $((RANDOM%COLUMNS+1)) $((RANDOM%8)); fi'
    hotdog003 · 2010-04-01 06:52:32 16
  • I save this to bin/iptrace and run "iptrace ipaddress" to get the Country, City and State of an ip address using the http://ipadress.com service. I add the following to my script to get a tinyurl of the map as well: URL=`lynx -dump http://www.ip-adress.com/ip_tracer/?QRY=$1|grep details|awk '{print $2}'` lynx -dump http://tinyurl.com/create.php?url=$URL|grep tinyurl|grep "19. http"|awk '{print $2}'


    24
    lynx -dump http://www.ip-adress.com/ip_tracer/?QRY=$1|grep address|egrep 'city|state|country'|awk '{print $3,$4,$5,$6,$7,$8}'|sed 's\ip address flag \\'|sed 's\My\\'
    leftyfb · 2009-02-25 17:16:56 27
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Get the total length of all videos in the current dir in H:m:s
You're behind on your TV catch-up, but how far behind? This command tries to open mplayer against all files in the current dir. If it's a video file it will contain ID_LENGTH, which is summed and output in hours, minutes and seconds. Someone better at awk could probably reduce this down a lot.

calculate md5 sums for every file in a directory tree
an alternative

Find name of package which installed a given shell command
Some command names are very different from the name of the package that installed them. Sometimes, you may want to find out the name of the package that provided a command on a system, so that you can install it on another system.

find out how much space are occuipied by files smaller than 1024K
The command gives size of all files smaller than 1024k, this information, together with disk usage, can help determin file system parameter (e.g. block size) or storage device (e.g. SSD v.s. HDD). Note if you use awk instead of "cut| dc", you easily breach maximum allowed number of records in awk.

Serve current directory tree at http://$HOSTNAME:8000/

spawn shell listener service with nc

Opens vi/vim at pattern in file
Open up vi or vim at the first instance of a pattern in [file]. Useful if you know where you want to be, like "PermitRootLogin" in sshd_config. Also, vi +10 [file] will open up a file at line 10. VERY useful when you get "error at line 10" type of output.

Debug SSH at the Maximum Verbosity Level
When debugging an ssh connection either to optimize your settings ie compression, ciphers, or more commonly for debugging an issue connecting, this alias comes in real handy as it's not easy to remember the '-o LogLevel=DEBUG3' argument, which adds a boost of debugging info not available with -vvv alone. Especially useful are the FD info, and the setup negotiation to create a cleaner, faster connection.

Pass TAB as field separator to sort, join, cut, etc.
Use this BASH trick to create a variable containing the TAB character and pass it as the argument to sort, join, cut and other commands which don't understand the \t notation. $ sort -t $'\t' ... $ join -t $'\t' ... $ cut -d $'\t' ...

colorize comm output
It just colorizes the line based on if it has 0, 1 or 2 tabs at the beginning of the line. Won't work so well if lines already begin with tabs (too bad comm doesn't have an option to substitute \t for something else). Don't forget comm needs input files to be sorted. You can use a shortcut like this with bash: comm


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