Most powerful examples of Unix commands or scripts

Question

There are many things that all programmers should know, but I am particularly interested in the Unix/Linux commands that we should all know. For accomplishing tasks that we may come up against at some point such as refactoring, reporting, network updates etc.

The reason I am curious is because having previously worked as a software tester at a software company while I am studying my degree, I noticed that all of developers (who were developing Windows software) had 2 computers.

To their left was their Windows XP development machine, and to the right was a Linux box. I think it was Ubuntu. Anyway they told me that they used it because it provided powerful unix operations that Windows couldn't do in their development process.

This makes me curious to know, as a software engineer what do you believe are some of the most powerful scripts/commands/uses that you can perform on a Unix/Linux operating system that every programmer should know for solving real world tasks that may not necessarily relate to writing code?

We all know what sed, awk and grep do. I am interested in some actual Unix/Linux scripting pieces that have solved a difficult problem for you, so that other programmers may benefit. Please provide your story and source.

I am sure there are numerous examples like this that people keep in their 'Scripts' folder.

Update: People seem to be misinterpreting the question. I am not asking for the names of individual unix commands, rather UNIX code snippets that have solved a problem for you.

Best answers from the Community

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Traverse a directory tree and print out paths to any files that match a regular expression:

find . -exec grep -l -e 'myregex' {} \; >> outfile.txt 

Invoke the default editor(Nano/ViM)

(works on most Unix systems including Mac OS X) Default editor is whatever your "EDITOR" environment variable is set to. ie: export EDITOR=/usr/bin/pico which is located at ~/.profile under Mac OS X.

Ctrl+x Ctrl+e

List all running network connections (including which app they belong to)

lsof -i -nP

Clear the Terminal's search history (Another of my favourites)

history -c

Answer 1

Your shell is the most powerful tool you have available

1. being able to write simple loops etc
2. understanding file globbing (e.g. *.java etc.)
3. being able to put together commands via pipes, subshells. redirection etc.

Having that level of shell knowledge allows you to do enormous amounts on the command line, without having to record info via temporary text files, copy/paste etc., and to leverage off the huge number of utility programs that permit slicing/dicing of data.

Unix Power Tools will show you so much of this. Every time I open my copy I find something new.