Bash Script Variable Substitution

Question

I'm trying to combine some text to a variable and output the value of the combined variable. For example:

testFILE=/tmp/some_file.log
function test_param {
echo $1
echo test$1
echo $(test$1) #this is where I want to output the value of the combined variable
}

test_param FILE

Output would be:

FILE
testFILE
/tmp/some_file.log  <-- this is what I can't figure out.

Any ideas?

If I'm not using the correct terminology please correct me.

Thanks, Jared

Answer 1

Try the following:

#!/bin/bash
testFILE=/tmp/some_file.log
function test_param {
    echo $1
    echo test$1
    varName=test$1
    echo ${!varName}
}

test_param FILE

The ! before varName indicates that it should look up the variable based on the contents of $varName, so the output is:

FILE
testFILE
/tmp/some_file.log