Bash variable usage

Question

I am confused by how to use variables in Bash. Please see the following example. I am not able to figure out why Bash isn't able to recognize the variable within (). Can anybody please help me understand what is going on.

$echo $SHELL
 /bin/bash
$export TestC=/Users
$echo $TestC
 /Users
$export TestD=$TestC/ABCD
$echo $TestD
/Users/ABCD
$export TestD=$(TestC)/ABCD
-bash: TestC: command not found

Thanks for your help

Thanks for your reply. Can you please help me understand what I am doing wrong. — user3357091
– user3357091, Commented May 14, 2017 at 14:14

Eric Renouf · Accepted Answer · 2017-05-14 14:20:00Z

4

When referencing a bash variable you either use $ then the name, as in $TestC or you can put braces around the name like ${TestC}.

$(...) is a subshell syntax called command substitution that will execute the command inside the parens then "return" the stdout of that command.

Read all about parameter/variable expansion here, which also shows a lot of the extra things you can do with the parameter expansion when using braces.

answered May 14, 2017 at 14:20

Eric Renouf

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