All commands

this is handy when the hubmachine is the only machine that can connect to the destination machine (allowed on ip by firewall) and you want to access it from your laptop.

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/

This command is useful for separating a text file where all the words are in one line. Any group of spaces will be replaced with a single newline. Instead of one long line of tokens. You'll have a long list of tokens. One token per line.

A simple way using a for loop

Simple way to get a timestamp from a date

If you have a file full of numbers written line by line, you can sum every line to get the total.

With a file like this:

3443535

9878977

67554

987798

232324

you will got:

14610188

This script first find all files which contains word xxxxx recursively. Then replace the word xxxxx to yyyyy of the files.

Use case:

- Web site domain change

- Function name change of the program

You can specify various output formats, theme styles, etc.

Check available output formats, styles, etc.:

Find pygments module here: http://pygments.org/

Useful when you want to quickly rename a bunch of files.

-p Tell me the name of the program and it's PID

-l that is listening

-u on a UDP port.

-n Give me numeric IP addresses (don't resolve them)

-t oh, also TCP ports

Seq allows you to define printf like formating by specified with -f, %03g is actually tells seq I got three digits, fill the blank digits with 0, and the range is from 176 to 240.

strace can be invaluable in trying to figure out what the heck some misbehaving program is doing. There are number of useful flags to limit and control its output, and to attach to already running programs. (See also 'ltrace'.)

You cannot kill zombies, as they are already dead. But if you have too many zombies then kill parent process or restart service.

You can kill zombie process using PID obtained from the above command. For example kill zombie proces having PID 4104:

# kill -9 4104

Please note that kill -9 does not guarantee to kill a zombie process.