Linux

7.11    Branches, Loops, and Functions

This section describes which bash keywords you can use to structure your code. You can create branches using if or case; loops using for, while, or until; functions using function; and so on.

7.11.1    If Branches

As in almost any programming language, you can formulate branches using if. The syntax is as follows:

if condition1; then     command1a    command1b[ elif condition2; then    commands2 ][ else    commands3 ]fi 

A concrete example looks as follows:

if [ $# -ne 2 ]; then    echo "Two parameters must be passed to the command!"    exit 2  # error code for wrong parameterselse    echo "Parameter 1: $1, Parameter 2: $2"fi 

The criterion for branching is the return value of the last command before then. The condition is met ...