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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 bash from sorted by
Terminal - Commands tagged bash - 706 results
vimdiff foo.c <(bzr cat -r revno:-2 foo.c)
for dir in $(ls); do du -sk ${dir}; done
2009-03-24 13:42:55
User: morlockhq_
Functions: dir du

Sometimes you want to know the summary of the sizes of directories without seeing the details in their subdirectories. Especially if it is going to just scroll off the screen. This one liner summarizes the disk usage of any number of directories in a directory without giving all the details of whats happening underneath.

for i in $(pgrep -v -u root);do kill -9 $i;done
2009-03-24 02:54:52
User: lostnhell
Functions: kill


grep -- displays process ids

-v -- negates the matching, displays all but what is specified in the other options

-u -- specifies the user to display, or in this case negate

The process loops through all PIDs that are found by pgrep, then orders a forced kill to the processes in numerical order, effectively killing the parent processes first including the shells in use which will force the users to logout.

Tested on Slackware Linux 12.2 and Slackware-current

addfunction () { declare -f $1 >> ~/.bashrc ; }
2009-03-23 12:55:04
User: dagh
Tags: bash

Example: To store the function addfunction after you have defined it:

addfunction addfunction
ls | while read ITEM; do echo "$ITEM"; done
2009-03-22 23:33:13
User: fletch
Functions: echo ls read
Tags: bash

If you want to operate on a set of items in Bash, and at least one of them contains spaces, the `for` loop isn't going to work the way you might expect. For example, if the current dir has two files, named "file" and "file 2", this would loop 3 times (once each for "file", "file", and "2"):

for ITEM in `ls`; do echo "$ITEM"; done

Instead, use a while loop with `read`:

ls | while read ITEM; do echo "$ITEM"; done
svn status app/models/foo.rb; svn commit -m "Changed file" !$
2009-03-22 23:14:06
User: ggoodale

After a command is run in bash, !$ is set to the last (space-delimited) argument of the command. Great for running several commands against the same file in a row.

for i in {1..15}; do echo $i; done
2009-03-21 23:08:41
User: haivu
Functions: echo
Tags: bash

The brace expansion also allows you to count backward:

for i in {15..1}; do echo $i; done

You can also use this construct to create new file or new directory:

mkdir dir{1..3} # Same as mkdir dir1 dir2 dir3

cat /proc/acpi/battery/BAT1/info
2009-03-21 06:09:37
User: Vlad003
Functions: cat
Tags: bash battery

Displays all information about your battery. for just capacity, try replacing cat with

grep -F capacity:

Battery number might be BAT0 instead of BAT1. Just run

cd /proc/acpi/battery; ls

and find out what folder is in that directory and replace that name with BAT1

fc [history-number]
2009-03-20 15:09:43
User: haivu
Functions: fc
Tags: bash

If you would like to edit a previous command, which might be long and complicated, you can use the fc (I think it stands for fix command). Invoke fc alone will edit the last command using the default editor (specified by $FCEDIT, $EDITOR, or emacs, in that order). After you make the changes in the editor, save and exit to execute that command. The fc command is more flexible than what I have described. Please 'man bash' for more information.

2009-03-20 14:50:25
User: haivu
Tags: bash

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.

alias ..='cd ..'
2009-03-20 09:57:28
User: eimantas
Functions: alias
Tags: bash unix shell cd

Alias two dots to move to parent directory. Put it into your .bashrc or .profile file.

( IFS=:; for p in $PATH; do echo $p; done )
2009-03-19 22:45:47
User: haivu
Functions: echo
Tags: bash

The output of "echo $PATH" is hard to read, this is much easier. The parentheses ensure that the change to the input field separator (IFS) only happens the the sub shell and not affecting the current shell.

^Z $bg $disown
2009-03-17 21:52:52
User: fall0ut

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...

2009-03-16 20:58:31
User: mallegonian
Tags: bash hotkey

Hold ctrl and press z to pause the current thread. Run


to resume it.

sort file1.txt | uniq > file2.txt
find . -print | sed -e 's;[^/]*/;|____;g;s;____|; |;g'
2009-03-12 22:25:26
Functions: find sed

NOT MINE! Taken from hackzine.com blog.

It creates a tree-style output of all the (sub)folders and (sub)files from the current folder and down(deeper)

Quoting some of hackzine's words

"Murphy Mac sent us a link to a handy find/sed command that simulates the DOS tree command that you might be missing on your Mac or Linux box. [..split...] Like most things I've seen sed do, it does quite a bit in a single line of code and is completely impossible to read. Sure it's just a couple of substitutions, but like a jack in the box, it remains a surprise every time I run it."

echo -n $HEXBYTES | xxd -r -p | dd of=$FILE seek=$((0x$OFFSET)) bs=1 conv=notrunc
2009-03-11 17:02:24
User: zombiedeity
Functions: dd echo

Replace (as opposed to insert) hex opcodes, data, breakpoints, etc. without opening a hex editor.

HEXBYTES contains the hex you want to inject in ascii form (e.g. 31c0)

OFFSET is the hex offset (e.g. 49cf) into the binary FILE

export PS1='\n[\u@\h \! \w]\n\[\e[32m\]$ \[\e[0m\]'
2009-03-09 15:34:22
User: haivu
Functions: export
Tags: bash

I put that line in my .bash_profile (OS X) and .bashrc (Linux).

Here is a summary of what the \char means: n=new line, u=user name, h=host, !=history number, w=current work directory

The \[\e[32m\] sequence set the text to bright green and \[\e[0m\] returns to normal color.

For more information on what you can set in your bash prompt, google 'bash prompt'

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 '^[^|,]*')
2009-03-09 03:57:44
User: lrvick
Functions: echo grep sed

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")")

tail -f *[!.1][!.gz]
2009-03-06 16:24:44
User: piscue
Functions: tail

with discard wilcards in bash you can "tail" newer logs files to see what happen, any error, info, warn...

echo 1 2 3 > FILE; while read -a line; do echo ${line[2]}; done < FILE
2009-03-06 15:32:40
User: occam
Functions: echo read
Tags: bash

This will print out the third column of every line in FILE. Useful for many files in /proc or *csv data.

find . -type d \( -name DIR1 -o -name DIR2 \) -prune -o -type f -print0 | xargs -r0 md5sum
2009-03-05 21:26:24
User: starchox
Functions: find xargs
Tags: bash

Useful if you want get all the md5sum of files but you want exclude some directories. If your list of files is short you can make in one command as follow:

find . -type d \( -name DIR1 -o -name DIR2 \) -prune -o -type f -exec md5sum {} \;

Alternatively you can specify a different command to be executed on the resulting files.

alias lh='ls -a | egrep "^\."'
ifconfig -a | nawk 'BEGIN {FS=" "}{RS="\n"}{ if($1~ /:/) {printf "%s ", $1}}{ if($1=="inet") {print " -- ",system("arp "$2)}}'|egrep -v "^[0-9]$"
2009-03-02 23:15:13
User: leprasmurf
Functions: ifconfig

Needed to get the Mac of various devices on a solaris box, but didn't have root. This command used awk to display the Network device, the IP, and the MAC a line at a time.

alias vb='vim ~/.bashrc; source ~/.bashrc'
2009-03-02 21:01:49
User: haivu
Functions: alias col groff man

Place the line above in your ~/.bahsrc file. Now every time you issue the 'vb' command, you invoke the vim editor to edit it, then source it so the changes take effect immediately.


* This mechanism is not working well if your .bashrc contains commands that should not be sourced more than once.

* This trick also work for your csh or tclsh users: place the following line in your ~/.cshrc file:

alias vc 'vim ~/.cshrc; source ~/.cshrc

Thank you adzap for pointing out the missing quote