Commands using read (336)


  • 8
    du -cks * | sort -rn | while read size fname; do for unit in k M G T P E Z Y; do if [ $size -lt 1024 ]; then echo -e "${size}${unit}\t${fname}"; break; fi; size=$((size/1024)); done; done
    askedrelic · 2010-04-05 17:09:14 0
  • find . -type f -iname '*.flac' # searches from the current folder recursively for .flac audio files | # the output (a .flac audio files with relative path from ./ ) is piped to while read FILE; do FILENAME="${FILE%.*}"; flac -cd "$FILE" | lame -b 192 - "${FILENAME}.mp3"; done # for each line on the list: # FILE gets the file with .flac extension and relative path # FILENAME gets FILE without the .flac extension # run flac for that FILE with output piped to lame conversion to mp3 using 192Kb bitrate Show Sample Output


    8
    find . -type f -iname '*.flac' | while read FILE; do FILENAME="${FILE%.*}"; flac -cd "$FILE" | lame -b 192 - "${FILENAME}.mp3"; done
    paulochf · 2010-08-15 19:02:19 0
  • Can be used for command line parameters too. If you have a more complicated way of entering values (validation, GUI, ...), then write a function i.e. EnterValue() that echoes the value and then you can write: param=${param:-$(EnterValue)}


    8
    param=${param:-$(read -p "Enter parameter: "; echo "$REPLY")}
    frans · 2011-09-08 20:48:31 0
  • I find it useless but definitely simpler than #9230 Show Sample Output


    8
    read -ra words <<< "<sentence>" && echo "${words[@]^}"
    RanyAlbeg · 2011-09-10 02:46:42 2
  • Certain Flash video players (e.g. Youtube) write their video streams to disk in /tmp/ , but the files are unlinked. i.e. the player creates the file and then immediately deletes the filename (unlinking files in this way makes it hard to find them, and/or ensures their cleanup if the browser or plugin should crash etc.) But as long as the flash plugin's process runs, a file descriptor remains in its /proc/ hierarchy, from which we (and the player) still have access to the file. The method above worked nicely for me when I had 50 tabs open with Youtube videos and didn't want to have to re-download them all with some tool.


    8
    lsof -n -P|grep FlashXX|awk '{ print "/proc/" $2 "/fd/" substr($4, 1, length($4)-1) }'|while read f;do newname=$(exiftool -FileModifyDate -FileType -t -d %Y%m%d%H%M%S $f|cut -f2|tr '\n' '.'|sed 's/\.$//');echo "$f -> $newname";cp $f ~/Vids/$newname;done
    mhs · 2012-02-25 01:49:45 1
  • client$ while true; do read -n30 ui; echo $ui |openssl enc -aes-256-ctr -a -k PaSSw ; done | nc localhost 8877 | while read so; do decoded_so=`echo "$so"| openssl enc -d -a -aes-256-ctr -k PaSSw`; echo -e "Incoming: $decoded_so"; done This will establish a simple encrypted chat with AES-256-CTR using netcat and openssl only. More info here https://nixaid.com/encrypted-chat-with-netcat/


    8
    server$ while true; do read -n30 ui; echo $ui |openssl enc -aes-256-ctr -a -k PaSSw; done | nc -l -p 8877 | while read so; do decoded_so=`echo "$so"| openssl enc -d -a -aes-256-ctr -k PaSSw`; echo -e "Incoming: $decoded_so"; done
    arno · 2014-01-16 14:36:09 0

  • 7
    read VAR1 VAR2 VAR3 < <(echo aa bb cc); echo $VAR2
    mikeda · 2009-02-22 10:05:50 6
  • Taking file with ip ranges, each on it's own line like: cat ipranges.txt 213.87.86.160-213.87.86.193 213.87.87.0-213.87.88.255 91.135.210.0-91.135.210.255 command returns deaggregated ip ranges using ipcalc deaggregate feature like that: 213.87.86.160/27 213.87.86.192/31 213.87.87.0/24 213.87.88.0/24 91.135.210.0/24 Useful for configuring nginx geo module Show Sample Output


    7
    /bin/grep - ipranges.txt | while read line; do ipcalc $line ; done | grep -v deag
    tf8 · 2010-04-20 21:13:00 0
  • Use this command if you want to rename all subtitles for them to have the same name as the mp4 files. NOTE: The order of "ls -1 *.mp4" must match the order of "ls -1 *.srt", run the command bellow to make sure the *.srt files will really match the movies after run this command: paste -d:


    7
    paste -d: <(ls -1 *.mp4) <(ls -1 *.srt) | while read line; do movie="${line%%:*}"; subtitle="${line##*:}"; mv "${subtitle}" "${movie%.*}.srt"; done
    ricardofunke · 2020-11-08 02:47:13 68

  • 6
    read -sn 1 -p 'Press any key to continue...';echo
    arcege · 2009-11-07 03:05:21 1
  • Just added -sn1 -s = silent -n1 = only one symbol needed to continue after the insert Show Sample Output


    6
    read -sn1 -p "Press any key to continue..."; echo
    vibaf · 2010-04-13 20:37:26 2
  • SH

    cat mod_log_config.c | shmore or shmore < mod_log_config.c Most pagers like less, more, most, and others require additional processes to be loaded, additional cpu time used, and if that wasn't bad enough, most of them modify the output in ways that can be undesirable. What I wanted was a "more" pager that was basically the same as running: cat file Without modifying the output and without additional processes being created, cpu used, etc. Normally if you want to scroll the output of cat file without modifying the output I would have to scroll back my terminal or screen buffer because less modifies the output. After looking over many examples ranging from builtin cat functions created for csh, zsh, ksh, sh, and bash from the 80's, 90s, and more recent examples shipped with bash 4, and after much trial and error, I finally came up with something that satisifed my objective. It automatically adjusts to the size of your terminal window by using the LINES variable (or 80 lines if that is empty) so This is a great function that will work as long as your shell works, so it will work just find if you are booted in single user mode and your /usr/bin directory is missing (where less and other pagers can be). Using builtins like this is fantastic and is comparable to how busybox works, as long as your shell works this will work. One caveat/note: I always have access to a color terminal, and I always setup both the termcap and the terminfo packages for color terminals (and/or ncurses and slang), so for that reason I stuck the tput setab 4; tput setaf 7 command at the beginning of the function, so it only runs 1 time, and that causes the -- SHMore -- prompt to have a blue background and bright white text. This is one of hundreds of functions I have in my http://www.askapache.com/linux-unix/bash_profile-functions-advanced-shell.html">.bash_profile at http://www.askapache.com/">AskApache.com, but actually won't be included till the next update. If you can improve this in any way at all please let me know, I would be very grateful! ( Like one thing I want is to be able to continue to the next screen by pressing any key instead of now having to press enter to continue) Show Sample Output


    6
    shmore(){ local l L M="`echo;tput setab 4&&tput setaf 7` --- SHMore --- `tput sgr0`";L=2;while read l;do echo "${l}";((L++));[[ "$L" == "${LINES:-80}" ]]&&{ L=2;read -p"$M" -u1;echo;};done;}
    AskApache · 2010-04-21 00:40:37 2

  • 6
    cat list|while read lines;do echo "USER admin">ftp;echo "PASS $lines">>ftp;echo "QUIT">>ftp;nc 192.168.77.128 21 <ftp>ftp2;echo "trying: $lines";cat ftp2|grep "230">/dev/null;[ "$?" -eq "0" ]&& echo "pass: $lines" && break;done
    FuRt3X · 2010-05-02 07:37:22 2
  • Plays the mp3 stream of The Current as a background job. When you are done run: fg %1 then to exit Quite possible with Growl for mac I'd guess, although have not tried. Libnotify needed for notification, stream will still work otherwise


    6
    mplayer http://minnesota.publicradio.org/tools/play/streams/the_current.pls < /dev/null | grep --line-buffered "StreamTitle='.*S" -o | grep --line-buffered "'.*'" -o > mus & tail -n0 -f mus | while read line; do notify-send "Music Change" "$line";done
    spiffwalker · 2010-05-09 17:51:40 0
  • Listens for events in the directory. Each created file is displayed on stdout. Then each fileline is read by the loop and a command is run. This can be used to force permissions in a directory, as an alternative for umask. More details: http://en.positon.org/post/A-solution-to-the-umask-problem%3A-inotify-to-force-permissions


    6
    inotifywait -mrq -e CREATE --format %w%f /path/to/dir | while read FILE; do chmod g=u "$FILE"; done
    dooblem · 2010-10-21 23:36:02 0
  • This is useful when watching a log file that does not contain timestamps itself. If the file already has content when starting the command, the first lines will have the "wrong" timestamp when the command was started and not when the lines were originally written.


    6
    tail -f file | while read line; do echo -n $(date -u -Ins); echo -e "\t$line"; done
    hfs · 2010-11-19 10:01:57 5

  • 6
    fdupes -r -1 path | while read line; do j="0"; for file in ${line[*]}; do if [ "$j" == "0" ]; then j="1"; else ln -f ${line// .*/} $file; fi; done; done
    piti · 2011-06-26 10:45:52 3
  • (Please see sample output for usage) Use any script name (the read command gets it) and it will be encrypted with the extension .crypt, i.e.: myscript --> myscript.crypt You can execute myscript.crypt only if you know the password. If you die, your script dies with you. If you modify the startup line, be careful with the offset calculation of the crypted block (the XX string). Not difficult to make script editable (an offset-dd piped to a gpg -d piped to a vim - piped to a gpg -c directed to script.new ), but not enough space to do it on a one liner. Sorry for the chmod on parentheses, I dont like "-" at the end. Thanks flatcap for the subshell abbreviation to /dev/null Show Sample Output


    6
    read -p 'Script: ' S && C=$S.crypt H='eval "$((dd if=$0 bs=1 skip=//|gpg -d)2>/dev/null)"; exit;' && gpg -c<$S|cat >$C <(echo $H|sed s://:$(echo "$H"|wc -c):) - <(chmod +x $C)
    rodolfoap · 2013-03-10 08:59:45 9
  • Usage exaple cmd echo 'Sure to continue ??'; read -n1 choi; if [ "$choi" = 'y' ] || [ "$choi" = 'Y' ]; then echo -e '\nExecuting..'; else echo 'Aborted'; fi Show Sample Output


    6
    read -N1
    totti · 2013-10-10 10:09:43 1
  • A bitcoin "brainwallet" is a secret passphrase you carry in your brain. The Bitcoin Brainwallet Private Key Base58 Encoder is the third of three functions needed to calculate a bitcoin PRIVATE key from your "brainwallet" passphrase. This base58 encoder uses the obase parameter of the amazing bc utility to convert from ASCII-hex to base58. Tech note: bc inserts line continuation backslashes, but the "read s" command automatically strips them out. I hope that one day base58 will, like base64, be added to the amazing openssl utility. Show Sample Output


    6
    function b58encode () { local b58_lookup_table=({1..9} {A..H} {J..N} {P..Z} {a..k} {m..z}); bc<<<"obase=58;ibase=16;${1^^}"|(read -a s; for b58_index in "${s[@]}" ; do printf %s ${b58_lookup_table[ 10#"$b58_index" ]}; done); }
    nixnax · 2014-02-18 02:29:30 1
  • A bitcoin "brainwallet" is a secret passphrase you carry in the "wallet" of your brain. The Bitcoin Brainwallet Private Key Calculator calculates the standard base58 encoded bitcoin private key from your "brainwallet" passphrase. The private key is the most important bitcoin number. All other numbers can be derived from it. This command uses 3 other functions - all 3 are defined on my user page: 1) brainwallet_exponent() - search for Bitcoin Brainwallet Exponent Calculator 2) brainwallet_checksum() - search for Bitcoin Brainwallet Exponent Calculator 3) b58encode() - search for Bitcoin Brainwallet Base58 Encoder Do make sure you use really strong, unpredictable passphrases (30+ characters)! http:brainwallet.org can be used to check the accuracy of this calculator. Show Sample Output


    6
    (read -r passphrase; b58encode 80$( brainwallet_exponent "$passphrase" )$( brainwallet_checksum "$passphrase" ))
    nixnax · 2014-02-18 02:50:09 1
  • When your wtmp files are being logrotated, here's an easy way to unpack them all on the fly to see more than a week in the past. The rm is the primitive way to prevent symlink prediction attack.


    5
    ( last ; ls -t /var/log/wtmp-2* | while read line ; do ( rm /tmp/wtmp-junk ; zcat $line 2>/dev/null || bzcat $line ) > /tmp/junk-wtmp ; last -f /tmp/junk-wtmp ; done ) | less
    DoNotRememberMe · 2010-03-16 04:17:16 0
  • This will save your open windows to a file (~/.windows). To start those applications: cat ~/.windows | while read line; do $line &; done Should work on any EWMH/NetWM compatible X Window Manager. If you use DWM or another Window Manager not using EWMH or NetWM try this: xwininfo -root -children | grep '^ ' | grep -v children | grep -v '<unknown>' | sed -n 's/^ *\(0x[0-9a-f]*\) .*/\1/p' | uniq | while read line; do xprop -id $line _NET_WM_PID | sed -n 's/.* = \([0-9]*\)$/\1/p'; done | uniq -u | grep -v '^$' | while read line; do ps -o cmd= $line; done > ~/.windows Show Sample Output


    5
    wmctrl -l -p | while read line; do ps -o cmd= "$(echo "$line" | awk '$0=$3')"; done > ~/.windows
    matthewbauer · 2010-07-04 22:11:24 2
  • Bash only, no sed, no awk. Multiple spaces/tabs if exists INSIDE the line will be preserved. Empty lines stay intact, except they will be cleaned from spaces and tabs if any available.


    5
    while read l; do echo -e "$l"; done <1.txt >2.txt
    knoppix5 · 2012-03-13 14:27:49 0

  • 5
    paste <(seq 7 | shuf | tr 1-7 A-G) <(seq 7 | shuf) | while read i j; do play -qn synth 1 pluck $i synth 1 pluck mix $2; done
    kev · 2012-04-09 15:22:19 0
  •  < 1 2 3 4 >  Last ›

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands


Check These Out

Display a block of text: multi-line grep with perl
-n reads input, line by line, in a loop sending to $_ Equivalent to while () { mycode } -e execute the following quoted string (i.e. do the following on the same line as the perl command) the elipses .. operator behaves like a range, remembering the state from line to line.

Function that counts recursively number of lines of all files in specified folders

Find usb device
I often use it to find recently added ou removed device, or using find in /dev, or anything similar. Just run the command, plug the device, and wait to see him and only him

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

Embed next line on the end of current line using sed
N: On the current line, sed will display it on pattern space, plus a \n (new line); but s/\n//: Will get rid of new line displayed on pattern space, joining the current line's end with the start of the next line Useful in scripts.

Record and share your terminal
It replays plain text terminal screencast from http://shelr.tv/

Get all available packages on Ubuntu (or any distro that uses apt)

Search google and show only urls
Get the first 10 google results form a querry, but showing only the urls from the results. Use + to search diferent terms, ex: commandlinefu+google .

Use GNU info with a pager
This makes GNU info output menu items recursively and pipe its contents to less, allowing one to use GNU info in a manner similar to 'man'.

Find the package that installed a command


Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: