Bash scripting

Increment variable in bash an math in general

How to increment a variable in bash? - Ask Ubuntu var=$((var + 1)) is the most portable one.

Redirecting stdout and stderr in bash

some_command >file.log 2>&1 is the only one that works for me in all cases. (shell - Redirect stderr and stdout in Bash - Stack Overflow)

Bash arbitrary number of arguments and their number

"$@" are the arguments one can iterate through, and "@#" is their number.