If-else, elif Conditional Execution in Shell Script

Conditional Execution

If else

It tests the result of a condition and if the condition is true then executes statement1, otherwise if else part is there then it executes the statement2.

if condition

then

statement1

else

statement2

fi

if else condition

Nested if - then - if statements

if condition

then

if condition

statement1

       fi

fi

Nested if else statements

For checking multiple conditions, the program can be written as

if condition

then

statement1

      else if condition

      statement2

      fi

else

statement 3

fi

Here else if can be replaced as elif also.

Example

#!/bin/sh if [ -f info ] then echo “info is a file”     elif [ -d info ]     then     echo “info is a directory” else echo “info is neither file nor directory” fi

this programs the file info either it is regular file or directory or other.