Do not expand variables in command line

[GoogleCodeExporter]

Suppose we try to run a command in inline mode:

$ ../seqpipe -e 'echo ${TEXT}' -h

Variables for inline command:
   TEXT                            Required


How about we specify the required variable as another bash environment variable?

$ ../seqpipe -e 'echo ${TEXT}' TEXT='${PATH}' -H

Variables for inline command:
   PATH                            Required

   TEXT                            Default: ${PATH}


Actually, seqpipe should not expand variables in command line, since they are 
not on the same explanation level.

Original issue reported on code.google.com by yanlinlin82 on 28 Sep 2013 at 3:45