$ variable resolution problem

Shell Programming and Scripting
1

We have the following code

filename=`head -1 $filelist`
if [ ! -f $filename ]
then
 touch $filename
fi

filelist contains the below items.

${HOME}/file1
${TEST_DIR}/file2
.
.

The output of the script described above is
${HOME} not found

The $ variables given inside the file list are not getting resolved.

Is it that the variables are not available as the script runs in a shell or something like that?

2

Use eval in front of touch. Existence of files is tested with -e not -f if that is what you want to do. And make sure $filelist is defined somewhere cause I could not see it.

3

Thanks a lot! Using eval in front of touch worked.

Can you please explain the use of eval in this context?

4

Echoing $filename should show you just the path without substitution of $HOME.

Era has a good description here:
http://www.unix.com/shell-programming-scripting/66063-eval-shell-scripting.html

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