Substituting variable values in a string

Question

I have a file (test.txt) with a line like this (verbatim):

MyCode $Cores

In a bash script, I have set the value of $Cores, so I want to execute the line from test.txt using this value. I tried this:

Cores=2
ProgramString=... read line from test.txt...
ProgramCommand=$(eval echo \$$ProgramString)
echo ${ProgramCommand}
${ProgramCommand}

The output is this:

$MyCode 2

It has successfully replaced $Cores with 2, but it has added a dollar sign at the beginning, so of course I get

$MyCode No such file or directory

Can anyone explain where this extra $ is coming from (and how to get rid of it)?

Answer 1

You included the $ with \\$ . Use ProgramCommand=$(eval echo $ProgramString) instead.