Commands tagged cat (49)

  • If you have a bunch of small files that you want to cat to read, you can cat each alone (boring); do a cat *, and you won't see what line is for what file, or do a grep . *. "." will match any string and grep in multifile mode will place a $filename: before each matched line. It works recursively too!! Show Sample Output

    grep . *
    theist · 2011-09-01 09:16:04 4
  • This command lets you see and scroll through all of the strings that are stored in the RAM at any given time. Press space bar to scroll through to see more pages (or use the arrow keys etc). Sometimes if you don't save that file that you were working on or want to get back something you closed it can be found floating around in here! The awk command only shows lines that are longer than 20 characters (to avoid seeing lots of junk that probably isn't "human readable"). If you want to dump the whole thing to a file replace the final '| less' with '> memorydump'. This is great for searching through many times (and with the added bonus that it doesn't overwrite any memory...). Here's a neat example to show up conversations that were had in pidgin (will probably work after it has been closed)... sudo cat /proc/kcore | strings | grep '([0-9]\{2\}:[0-9]\{2\}:[0-9]\{2\})' (depending on sudo settings it might be best to run sudo su first to get to a # prompt)

    sudo cat /proc/kcore | strings | awk 'length > 20' | less
    nesquick · 2009-03-09 02:19:47 5
  • Files containing ascii art (e.g. with .nfo extension) are typically not correctly reproduced at the command line when using cat. With iconv one can easily write a wrapper to solve this: #!/bin/bash if [ -z "$@" ]; then echo "Usage: $(basename $0) file [file] ..." else iconv -f437 -tutf8 "$@"; fi exit 0

    iconv -f437 -tutf8 asciiart.nfo
    speaker · 2009-07-11 23:50:05 1
  • The format is JJJJJ YR-MO-DA HH:MM:SS TT L DUT1 msADV UTC(NIST) OTM and is explained more fully here: Show Sample Output

    cat </dev/tcp/
    drewk · 2009-12-03 21:40:14 6
  • 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">.bash_profile at">, 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

    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 1
  • the tee command does fine with file names, but not so much with file descriptors, such as &2 (stderr). This uses process redirection to tee to the specified descriptor. In the sample output, it's being used to tee to stderr, which is connected with the terminal, and to wc -l, which is also outputting to the terminal. The result is the output of bash --version followed by the linecount Show Sample Output

    tee >(cat - >&2)
    camocrazed · 2010-07-20 17:22:31 3

  • 5
    cat -n file.txt
    ztank1013 · 2011-09-14 20:38:41 0
  • Useful to detect number of tabs in an empty line, DOS newline (carriage return + newline). A tool that can help you understand why your parsing is not working. Show Sample Output

    cat -v -t -e
    alperyilmaz · 2009-03-24 19:29:03 1

  • 4
    cat -n
    putnamhill · 2009-12-08 16:35:55 2
  • This takes a webcam picture every everytime the mouse is moved (waits 10 seconds between checking for movement) and stores the picture wherever you want it. Ideas: Use in conjunction with a dropbox type application to see who is using your computer Use /dev/input/mice if /dev/input/mouse* doesn't work Use the bones of this to make a simple screensaver

    while true; do sudo cat /dev/input/mouse0|read -n1;streamer -q -o /tmp/cam.jpeg -s 640x480 > /dev/null 2>&1; sleep 10;done
    SQUIIDUX · 2012-04-22 01:51:30 1

  • 3
    cat /proc/net/ip_conntrack | grep ESTABLISHED | grep -c -v ^#
    flamarion · 2009-07-29 20:21:25 2
  • Pipe any output to "grep ." and blank lines will not be printed.

    cat filename | grep .
    fraktil · 2009-08-09 01:00:59 1
  • random(6) - random lines from a file or random numbers

    random -f <file>
    haplo · 2009-09-24 19:15:58 4
  • This just reads in a local file and sends it via email. Works with text or binary. *Requires* local mail server.

    cat filename | mail -s "Email subject"
    topher1kenobe · 2009-09-20 01:38:23 0
  • This uses some tricks I found while reading the bash man page to enumerate and display all the current environment variables, including those not listed by the 'env' command which according to the bash docs are more for internal use by BASH. The main trick is the way bash will list all environment variable names when performing expansion on ${!A*}. Then the eval builtin makes it work in a loop. I created a function for this and use it instead of env. (by aliasing env). This is the function that given any parameters lists the variables that start with it. So 'aae B' would list all env variables starting wit B. And 'aae {A..Z} {a..z}' would list all variables starting with any letter of the alphabet. And 'aae TERM' would list all variables starting with TERM. aae(){ local __a __i __z;for __a in "$@";do __z=\${!${__a}*};for __i in `eval echo "${__z}"`;do echo -e "$__i: ${!__i}";done;done; } And my printenv replacement is: alias env='aae {A..Z} {a..z} "_"|sort|cat -v 2>&1 | sed "s/\\^\\[/\\\\033/g"' From: Show Sample Output

    for _a in {A..Z} {a..z};do _z=\${!${_a}*};for _i in `eval echo "${_z}"`;do echo -e "$_i: ${!_i}";done;done|cat -Tsv
    AskApache · 2010-10-27 07:16:54 0
  • Randomizes a file. The opposite of sort is sort -R!

    sort -R
    RyanM · 2011-07-15 15:35:27 0
  • this will open a new tab in firefox for every line in a file the sleep is removable but i found that if you have a large list of urls 50+, and no sleep, it will try to open all the urls at once and this will cause them all to load a lot slower, also depending on the ram of your system sleep gives you a chance to close the tabs before they overload your ram, removing & >2/dev/null will yield unpredictable results.

    for line in `cat $file`; do firefox -new-tab "$line" & 2>/dev/null; sleep 1; done
    hamsolo474 · 2011-11-12 13:47:24 0
  • Merge Multiple PDFs In Alphabetical Order

    pdftk *.pdf cat output merged.pdf
    o0110o · 2014-03-02 01:53:37 0
  • Takes input from the connected terminal and dumps it to the specified file. Stop writing and close file with control + D or the end of line character. Useful for copying+pasting large blobs of text over SSH to a new machine. Show Sample Output

    cat /dev/tty > FILE
    Jo · 2009-02-25 01:43:47 5
  • Count your source and header file's line numbers. This ignores blank lines, C++ style comments, single line C style comments. This will not ignore blank lines with tabs or multiline C style comments.

    find /usr/include/ -name '*.[c|h]pp' -o -name '*.[ch]' -print0 | xargs -0 cat | grep -v "^ *$" | grep -v "^ *//" | grep -v "^ */\*.*\*/" | wc -l
    unixmonkey44446 · 2013-06-17 08:37:37 0
  • Prepend text to a file. It doen't need temporary files, ed or sed.

    echo "text to prepend" | cat - file
    leni536 · 2013-12-18 15:54:17 3
  • on some distro's you have to replace "BogoMIPS" with "bogomips". Show Sample Output

    cat /proc/cpuinfo | grep BogoMIPS | uniq | sed 's/^.*://g' | awk '{print($1 / 4) }'
    derpat · 2014-03-01 03:44:03 0
  • Save the script as: sort_file Usage: sort_file < sort_me.csv > out_file.csv This script was originally posted by Admiral Beotch in on the Linux-Software forum. I modified this script to make it more portable. Show Sample Output

    infile=$1 for i in $(cat $infile) do echo $i | tr "," "\n" | sort -n | tr "\n" "," | sed "s/,$//" echo done
    iframe · 2009-07-12 21:23:37 0
  • uuencode the file to appear as an attachment

    cat filename | uuencode filename | mail -s "Email subject"
    amaymon · 2009-09-21 04:13:50 6
  • The sort utility is well used, but sometimes you want a little chaos. This will randomize the lines of a text file. BTW, on OS X there is no | sort -R option! There is also no | shuf These are only in the newer GNU core... This is also faster than the alternate of: | awk 'BEGIN { srand() } { print rand() "\t" $0 }' | sort -n | cut -f2- Show Sample Output

    cat ~/SortedFile.txt | perl -wnl -e '@f=<>; END{ foreach $i (reverse 0 .. $#f) { $r=int rand ($i+1); @f[$i, $r]=@f[$r,$i] unless ($i==$r); } chomp @f; foreach $line (@f){ print $line; }}'
    drewk · 2009-09-24 15:42:43 2
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awk date convert
Convert readable date/time with `date` command

calulate established tcp connection of local machine
If you want prepend/append text just wrap in echo: $echo Connected: `netstat -an|grep -ci "tcp.*established"`

Make vim open in tabs by default (save to .profile)
I always add this to my .profile rc so I can do things like: "vim *.c" and the files are opened in tabs.

Gets the english pronunciation of a phrase
Usage examples: say hello say "hello world" say hello+world

A simple command to toggle mute with pulseaudio (any sink)
0 can also be replaced by the source name, e.g. alsa_output.pci-0000_00_1b.0.analog-stereo

show dd progress
if you need see progress of long dd command, enter subj on other console

Selecting a random file/folder of a folder
I used only shuf command.

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"

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"

Alias TAIL for automatic smart output
Run the alias command, then issue $ps aux | tail 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 default of 80. The default for TAIL is to output the last 10 lines, this alias changes the default to output the last x lines instead, where x is the number of lines currently displayed on your terminal - 7. The -7 is there so that the top line displayed is the command you ran that used TAIL, 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. ( ) 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.

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