Although Exim will purge frozen (undeliverable) messages over time, the command "exim -Mrm #id#" where #id# is a particular message ID will purge a message immediately. Being lazy, I don't want to type the command for each frozen message, so I wrote the one-liner to do it for me.

combines mkdir and cd

added quotes around $_, thanx to flatcap!

With counter format [001, 002, ..., 999] , nice with pictures or wallpapers collections.

Recursively rename .JPG to .jpg using standard find and mv. It's generally better to use a standard tool if doing so is not much more difficult.

In bash, by pressing ALT+n and then a character x, x will be printed n times

I know is not the same as the original command, but is correlated.

sed already has an option for editing files in place and making backup copies of the old file. -i will edit a file in place and if you give it an argument, it will make a backup file using that string as an extension.

how to finish command or script without any output

Quick and easy way to find out which php.ini file is being used. Especially useful if you just need to find the location of the file for editing purposes.

A really fun vim oneliner for auto documenting your option's parsing in your script.

# print the text embeded in the case that parse options from command line.

# the block is matched with the marker 'CommandParse' in comment, until 'esac'

extract_cmdl_options()

{

# use vim for parsing:

# 1st grep the case block and copy in register @p + unindent in the buffer of the file itself

# 2nd filter lines which start with --opt or +opt and keep comment on hte following lines until an empty line

# 3rd discard changes in the buffer and quit

vim -n -es -c 'g/# CommandParse/+2,/^\s\+esac/-1 d p | % d | put p | %

-c 'g/^\([-+]\+[^)]\+\))/,/^\(\s\+[^- \t#]\|^$\)/-1 p' \

-c 'q!' $0

}

example code:http://snipplr.com/view/25059/display-embeded-comments-for-every-opt-usefull-for-auto-documenting-your-script/

Manpages, command summaries, and pretty much everything else usually have the information you're most likely to want at the beginning. Seeing just the last 40 or so lines of options from a command that has 100 is not super useful, and having to scroll up each time you want to glance at something is spastic.

Run this and then do something like

and you'll get the first screen(-mostly-)full of vi's usage info and options list

Then use

to page down, and

to page up.

To see the current page again:

Also useful for situations like

where you're using readline up-arrow, HOME, END, etc., to quickly recall commented commands.

For the unaware, that option to aptitude search will bring up all of the packages whose descriptions contain the string "smorgasbord". Depending on your distro, there could potentially be hundreds of them.

Displays a scrolling banner which loops until you hit Ctrl-C to terminate it.

Make sure you finish your banner message with a space so it will loop nicely.

If you have some drive imaging to do, you can boot into any liveCD and use a commodity machine. The drives will be written in parallel.

To improve efficiency, specify a larger block size in dd:

To image more drives , insert them as additional arguments to tee:

Hi glaudiston, you can save a few chars by leaving out cat and pipe and still enjoy the added flexibility.

Execute this in the root of your music library and this recurses through the directories and normalizes each folder containing mp3s as a batch. This assumes those folders hold an album each. The command "normalize-audio" may go by "normalize" on some systems.

This version uses host and no ruby.

If you are interested in interfaces other than eth0 you will need to change eth0 to your interface name.

You could use this mammoth to nab the ip4 addresses of all your interfaces

perl -e '@_=`ifconfig -a`; sort(@_); foreach(@_) { /(inet addr\:)(\d+.\d+.\d+.\d+ )/; $_=$2; @uniq=grep($_ ne $prev && (($prev) = $_), @_);} print join "\n",@uniq,"\n"; '

it seems silly to have all this code when the following will work fine

ifconfig -a | grep "inet " | awk -F":" ' { print $2 } ' | cut -d " " -f1

Same thing just a different way to get there. You will need lynx

You can use [n]> combined with >(cmd) to attach the various output file descriptors to be the input of different commands.

if you still get a permissions error using sudo, then nano the file:

sudo nano -w /sys/block/sdb/queue/rotational

and change 1 to 0

this thread:

http://www.ocztechnologyforum.com/forum/showpost.php?p=369836&postcount=15

says that this will "help the block layer to optimize a few decisions"

The iostat command is used for monitoring system input/output device loading by observing the time the devices are active in relation to their average transfer rates.

in ubuntu to get the iostat program do this:

sudo apt-get install sysstat

i found this command here:

http://www.ocztechnologyforum.com/forum/showthread.php?t=54379

This function displays the latest comic from xkcd.com. One of the best things about xkcd is the title text when you hover over the comic, so this function also displays that after you close the comic.

To get a random xkcd comic, I also use the following:

Barely worth posting because it is so simple, but I use it literally all the time. I was always frustrated by the limitations that a non-gui environment imposes on diff'ing files. This fixes some of those limitations by colourising the output (you'll have to install colordiff, but it is just a wrapper for diff itself), using side-by-side mode for clearer presentation, and of course, the -W parameter, using tput to automatically insert you terminal width. Note that the double quotes aren't necessary if typed into terminal as-is. I included them for safety sake,