Command Substitution

GNU/Linux Command-Line Tools Summary
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6.3. Command Substitution

Command substitution is basically another way to do a pipe, you can use pipes and command substitution interchangeably, it's up to you which one you find easier...

Command substitution can be done in two distinct ways.

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Method�One�(back-quotes)

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Simply type:

command_1 `command_2 -options`

This will execute “command_2” and it's output will become the input to “command_1”.

	Backquote key
	The back-quote key is usually located at the same place as the tilde, above the [Tab] key.

Method�Two�(dollars�sign)

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Simply type:

command_1 $(command_2)

This will execute “command_2” and it's output will become the input to “command_1”.

Using�the�pipe�instead

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You can of course use pipes to do the same thing, if you don't know what a pipe is, please see Section 6.2. For example instead of doing:

less $cat file1.txt file2.txt

You could do:

cat file1.txt file2.txt | less

And end up with exactly the same result, it's up to you which way you find easier.

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