Question

I have a bash script that creates a Subversion patch file for the current directory. I want to modify it to zip the produced file, if -z is given as an argument to the script.

Here’s the relevant part:

zipped='' zipcommand='>'  if [ '$1' = '-z' ] then    zipped='zipped '    filename='${filename}.zip'    zipcommand='| zip >' fi  echo 'Creating ${zipped}patch file $filename...'  svn diff $zipcommand $filename 

This doesn’t work because it passes the | or > contained in $zipcommand as an argument to svn.

I can easily work around this, but the question is whether it’s ever possible to use these kinds of operators when they’re contained in variables.

Thanks!

Answer 1

I would do something like this (use bash -c or eval):

zipped='' zipcommand='>'  if [ '$1' = '-z' ] then    zipped='zipped '    filename='${filename}.zip'    zipcommand='| zip -@' fi  echo 'Creating ${zipped}patch file $filename...'  eval 'svn diff $zipcommand $filename' # this also works:  # bash -c 'svn diff $zipcommand $filename' 

This appears to work, but my version of zip (Mac OS X) required that i change the line:

zipcommand='| zip -@' 

to

zipcommand='| zip - - >' 

Edit: incorporated @DanielBungert’s suggestion to use eval