Set Bash variable to command output: Quick guide

If you need to store the output of a command in a Bash variable, there are several methods you can use. In this quick guide, we'll cover three simple ways to set a Bash variable to the output of a command.

Method 1: Command substitution

One way to set a Bash variable to the output of a command is to use command substitution. You can do this by enclosing the command in backticks (`command`) or using the newer syntax of enclosing the command in parentheses with a dollar sign ($()):

var=`command`
var=$(command)

For example, if you want to set a variable called "date" to the current date, you can use the "date" command like this:

date=`date`
date=$(date)

Method 2: Using a pipe

Another way to set a Bash variable to the output of a command is to use a pipe. You can do this by piping the output of the command to the "read" command, which will read the output into a variable:

command | read var

For example, if you want to set a variable called "diskusage" to the disk usage of your system, you can use the "df" command like this:

df -h | awk 'NR==2{print $5}' | read diskusage

Method 3: Using process substitution

The third way to set a Bash variable to the output of a command is to use process substitution. You can do this by enclosing the command in parentheses with a less than sign (<) before it:

var=<(command)

For example, if you want to set a variable called "files" to a list of files in a directory, you can use the "ls" command like this:

files=<(ls)

These three methods are simple and effective ways to set a Bash variable to the output of a command. Choose the one that works best for your situation and start using it today!