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2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.




Commands tagged cat from sorted by
Terminal - Commands tagged cat - 47 results
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;}
2010-04-21 00:40:37
User: AskApache
Functions: echo read
cat mod_log_config.c | shmore


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)

cat file1 ... fileN > combinedFile;
2010-04-17 01:00:04
User: GinoMan2440
Functions: cat
Tags: cat bash Linux

the last person who posted used the most roundabout way to concatinate files, there's a reason there's a "conCATinate" command... Using this method, you also get to choose the order of the files, below another person just did *.txt > combined.txt which is fine but the order depends on the implementation of "cat" which is probably alphabetical order of filenames.

perl -wl -e '@f=<>; for $i (0 .. $#f) { $r=int rand ($i+1); @f[$i, $r]=@f[$r,$i] if ($i!=$r); } chomp @f; print join $/, @f;' try.txt
ps aux | grep [h]ttpd | cat -n
2009-12-17 20:45:44
User: putnamhill
Functions: cat grep ps
Tags: cat

If you're on a system that doesn't have nl, you can use cat -n.

{ echo -e "$body"; uuencode "$outfile" "$outfile"; } | mail -s "$subject" "$destaddr" ;
2009-12-10 18:08:59
User: glaudiston
Functions: echo mail uuencode
Tags: cat mail

on this way we can define the body too

cat -n
cat </dev/tcp/time.nist.gov/13
2009-12-03 21:40:14
User: drewk
Functions: cat
Tags: cat tcp


and is explained more fully here: http://tf.nist.gov/service/acts.htm

cat /var/log/httpd/access_log | grep q= | awk '{print $11}' | awk -F 'q=' '{print $2}' | sed 's/+/ /g;s/%22/"/g;s/q=//' | cut -d "&" -f 1 | mail youremail@isp.com -s "[your-site] search strings for `date`"
2009-11-22 03:03:06
User: isma
Functions: awk cat grep sed strings

It's not a big line, and it *may not* work for everybody, I guess it depends on the detail of access_log configuration in your httpd.conf. I use it as a prerotate command for logrotate in httpd section so it executes before access_log rotation, everyday at midnight.

dd if=/dev/hda of=file.img
cat /dev/hda > ~/hda.iso
random -f <file>
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; }}'
2009-09-24 15:42:43
User: drewk
Functions: cat perl

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-
cat filename | uuencode filename | mail -s "Email subject" user@example.com
2009-09-21 04:13:50
User: amaymon
Functions: cat mail uuencode
Tags: cat mail

uuencode the file to appear as an attachment

cat filename | mail -s "Email subject" user@example.com
2009-09-20 01:38:23
Functions: cat mail
Tags: cat mail

This just reads in a local file and sends it via email. Works with text or binary. *Requires* local mail server.

cat filename | grep .
2009-08-09 01:00:59
User: fraktil
Functions: cat grep
Tags: cat Linux grep

Pipe any output to "grep ." and blank lines will not be printed.

cat /proc/net/ip_conntrack | grep ESTABLISHED | grep -c -v ^#
infile=$1 for i in $(cat $infile) do echo $i | tr "," "\n" | sort -n | tr "\n" "," | sed "s/,$//" echo done
2009-07-12 21:23:37
User: iframe
Functions: cat echo sed sort tr
Tags: cat bash sort sed tr

Save the script as: sort_file

Usage: sort_file < sort_me.csv > out_file.csv

This script was originally posted by Admiral Beotch in LinuxQuestions.org on the Linux-Software forum.

I modified this script to make it more portable.

iconv -f437 -tutf8 asciiart.nfo
2009-07-11 23:50:05
User: speaker
Functions: iconv

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:


if [ -z "$@" ]; then echo "Usage: $(basename $0) file [file] ..."

else iconv -f437 -tutf8 "$@"; fi

exit 0
cat -v -t -e
2009-03-24 19:29:03
User: alperyilmaz
Functions: cat
Tags: cat

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.

cat schema.sql data.sql test_data.sql | mysql -u user --password=pass dbname
2009-03-24 08:39:40
User: tristan_ph
Functions: cat
Tags: mysql cat

Be aware of using the --password argument as it will appear your password in plain text on the screen. You may use -p argument instead, it will prompt you to enter you password in hidden mode.

sudo cat /proc/kcore | strings | awk 'length > 20' | less
2009-03-09 02:19:47
User: nesquick
Functions: awk cat strings sudo
Tags: cat ram strings

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)

cat /dev/tty > FILE
2009-02-25 01:43:47
User: Jo
Functions: cat

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.