All commands

As an alternative to using an additional grep -v grep you can use a simple regular expression in the search pattern (first letter is something out of the single letter list ;-)) to drop the grep command itself.

Many like to use 'dd' for creating CD/DVD iso images. This is bad. Very bad. The reason this is, is 'dd' doesn't have any built-in error checking. So, you don't know if you got all the bits or not. As such, it is not the right tool for the job. Instead, 'reaom' (read optical media) from the wodim package is what you should be using. It has built-in error checking. Similarly, if you want to burn your newly creating ISO, stay away from 'dd', and use:

Prints a graphical directory tree from your current directory

defines a handy function for quick calculations from cli.

once defined:

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...

Pipe viewer is a terminal-based tool for monitoring the progress of data through a pipeline. It can be inserted into any normal pipeline between two processes to give a visual indication of how quickly data is passing through, how long it has taken, how near to completion it is, and an estimate of how long it will be until completion. Source: http://www.catonmat.net/blog/unix-utilities-pipe-viewer/

Similarly, if you want to print from 10 to the end of line you can use: sed -n '10,$p' filename

This is especially useful if you are dealing with a large file. Sometimes you just want to extract a sample without opening the entire file.

Credit goes to wbx & robert at the comments section of http://www.commandlinefu.com/commands/view/348/get-line1000-from-text.#comment

Written for linux, the real example is how to produce ascii text graphs based on a numeric value (anything where uniq -c is useful is a good candidate).

"-o loop" lets you use a file as a block device

This command displays a clock on your terminal which updates the time every second. Press Ctrl-C to exit.

A couple of variants:

A little bit bigger text:

You can try other figlet fonts, too.

Big sideways characters:

This requires a particular version of banner and a 40-line terminal or you can adjust the width ("30" here).

The title is optional.

Options:

-t: expire time in milliseconds.

-u: urgency (low, normal, critical).

-i: icon path.

On Debian-based systems you may need to install the 'libnotify-bin' package.

Useful to advise when a wget download or a simulation ends. Example:

Find random strings within /dev/urandom. Using grep filter to just Alphanumeric characters, and then print the first 30 and remove all the line feeds.

This will create the intermediate directories that do not exist.

I did not know about this for a long time.

Checks the Gmail ATOM feed for your account, parses it and outputs a list of unread messages.

For some reason sed gets stuck on OS X, so here's a Perl version for the Mac:

If you want to see the name of the last person, who added a message to the conversation, change the greediness of the operators like this:

This example, for example, produces the output, "Fri Feb 13 15:26:30 EST 2009"

for one line per process:

for established sockets only:

for just process names:

or

Of course you need to be able to access host A for this ;-)

Watch is a very useful command for periodically running another command - in this using mysqladmin to display the processlist. This is useful for monitoring which queries are causing your server to clog up.

More info here: http://codeinthehole.com/archives/2-Monitoring-MySQL-processes.html

This version uses read instead of eval.

This dup finder saves time by comparing size first, then md5sum, it doesn't delete anything, just lists them.