CODEWITHSUNDEEP
pythonsubprocess
kgully
kgully

Reputation: 662

Python subprocess gives syntax error but runs from shell

I am trying to run a shell command from python, and getting syntax errors. It is probably related to the fact that there are nested quotes, but I can't figure out how to make it work.

Here is the command:

In [44]: command
Out[44]: '/Applications/itt/idl/bin/idl -e "print, barycorr(2456718.886512, 16.109814, -36.799472, 0, obsname=\'CTIO\')"'

In [45]: print command
/Applications/itt/idl/bin/idl -e "print, barycorr(2456718.886512, 16.109814, -36.799472, 0, obsname='CTIO')"

When I run the command using either of the two below, I get a syntax error in idl:

subprocess.call(command, shell=True)
subprocess.call(shlex.split(command))

If I run the command (output of [45]) from the command line, it works perfectly. Any idea what I am doing wrong?

Thanks!

Upvotes: 2

Views: 2228

Answers (1)

Don Question
Don Question

Reputation: 11614

Try to construct your list manually, eg.:

cmd_lst = ['/Applications/itt/idl/bin/idl',
           '-e',
           ("print, barycorr(2456718.886512, 16.109814, -36.799472, 0,"
            " obsname='CTIO')"),
           ]

subprocess.call(cmd_lst)

I splitted the long string into two lines. The parenthesis makes sure it's handled as the same string even if spanning over multiple lines. As a side-effect the escapes for the single quotes may be omitted if not needed by the called program.

Upvotes: 1

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