title: python subprocess.call() "no such file or directory"
body: <p>I've found a few questions on the module but the more common problem seems to be getting the argument list right which I think I have managed (eventually)</p>
  
  <p>I am trying to run a program that expects an input like this in the command line,</p>
  
  <pre><code>fits2ndf in out
  </code></pre>
  
  <p>with 'in' being the filepath of the file to be converted and 'out' being the path and filename to save the result to.</p>
  
  <p>So using Subprocess,</p>
  
  <pre><code>subprocess.call(["fits2ndf","/media/tom_hdd/Transfer/reference.fits","/media/tom_hdd/Transfer/reference.sdf"])
  </code></pre>
  
  <p>this raises,</p>
  
  <pre><code>Traceback (most recent call last):
  File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  File "/usr/lib/python2.7/subprocess.py", line 493, in call
  return Popen(*popenargs, **kwargs).wait()
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
  errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
  raise child_exception
  OSError: [Errno 2] No such file or directory
  </code></pre>
  
  <p>Setting <code>shell=TRUE</code> (which I know is bad) produces the same result. Not sure if it is relevant but I am using tcsh. Any suggestions?</p>
  
  <hr>
  
  <p>Edit in response to questions</p>
  
  <p>I haven't permanently set the PATH however <code>fits2ndf</code> is part of a package of programs which I initialize using</p>
  
  <pre><code>% tcsh
  % setenv STARLINK_DIR  /home/tomq/star-kapuahi
  % source $STARLINK_DIR/etc/login
  % source $STARLINK_DIR/etc/cshrc
  </code></pre>
  
  <p>and normally works from within any directory without specifying the full path.</p>