The select, while, and until loops

The select, while and until loops are also used to loop and iterate over each item in a list or till the condition is true with slight variations in syntax.

Loop using select

The select loop helps in creating a numbered menu in an easy format from which a user can select one or more options.

The syntax of the select loop is as follows:

select var in list
do
   # Tasks to perform
done

The list can be pre-generated or specified while using the select loop in the form [item1 item2 item3 …].

For example, consider a simple menu listing the contents of '/' and asking a user to enter an option for which you want to know whether it is a directory or not:

#!/bin/bash
# Filename: select.sh
# Description: Giving user choice using select to choose

select file in 'ls /'
do
   if [ -d "/"$file ]
   then
     echo "$file is a directory"
   else
     echo "$file is not a directory"
  fi
done

The following is the screenshot of the output after running the script:

To exit from the...