Using GMT from Python by subprocess and shlex packages (redirect).

gmt_subprocess_redirect.py

# -*- coding: utf-8 -*-
from __future__ import (absolute_import, division,
                        print_function, unicode_literals)
from future_builtins import *
import shlex
import subprocess
import os


class ScriptRunningError(Exception):
    pass


def runScript(script):
    """ Run shell script depend on os environ.
        Can use writing and appending mode by redirect ('>' or '>>').

        :param str script: running script
    """
    script_list = shlex.split(script)
    if '>' in script_list:
        # Writing mode
        output_file = script_list[script_list.index('>') + 1]
        script_pre = script_list[:script_list.index('>')]
        with open(output_file, 'w') as f:
            proc = subprocess.Popen(script_pre, env=os.environ,
                                    stdout=f, stderr=subprocess.PIPE)
    elif '>>' in script_list:
        # Appending mode
        output_file = script_list[script_list.index('>>') + 1]
        script_pre = script_list[:script_list.index('>>')]
        with open(output_file, 'a') as f:
            proc = subprocess.Popen(script_pre, env=os.environ,
                                    stdout=f, stderr=subprocess.PIPE)
    elif ('>' in script) or ('>>' in script):
        raise ScriptRunningError("Please insert a space before and after"
                                 " the redirect $ %s" % str(script))
    else:
        proc = subprocess.Popen(script_list, env=os.environ,
                                stdout=subprocess.PIPE,
                                stderr=subprocess.PIPE)
    # stdout and stderr simply wait for script
    stdout, stderr = proc.communicate()
    retcode = proc.returncode
    del proc
    if retcode == 1:
        raise ScriptRunningError('This script could not run $ %s\n%s' % (
                                 str(script), str(stderr)))
    else:
        return True

if __name__ == '__main__':
    script = "gmt --version > sample.txt"
    runScript(script)

sample.txt

5.1.1