Linux basics

What version / flavor of Linux are you running ?

The command for this

Using /proc/version

In the terminal type

cat /proc/version
The output would be like
Linux version 2.6.13-15-default (geeko@buildhost) (gcc version 4.0.2 20050901 (prerelease) (SUSE Linux)) #1 Tue Sep 13 14:56:15 UTC 2005

which command

tells you whether an application is installed and the root path where it is installed

[user@rakhipbhatia2 ~]$ which bash

/bin/bash

[user@rakhipbhatia2 ~]$ which awk

/bin/awk

[user@rakhipbhatia2 ~]$ which sed

/bin/sed