在pyprof2calltree这个项目中学到的在系统中查看命令是否存在

find-cmd-exists.py

# coding=utf-8
"""
在pyprof2calltree这个项目中学到的在系统中查看命令是否存在
https://github.com/pwaller/pyprof2calltree/blob/master/pyprof2calltree.py

    :copyright: (c) 2016 by fangpeng(@beginman.cn).
    :license: MIT, see LICENSE for more details.
"""
import os
import sys
import subprocess

KCACHEGRIND_EXECUTABLES = ["kcachegrind", "qcachegrind"]


def is_basestring(s):
    try:
        u = unicode
        # Python 2.x
        return isinstance(s, basestring)
    except NameError:
        # Python 3.x
        return isinstance(s, (str, bytes))


def is_installed(prog):
    """Return whether or not a given executable is installed on the machine."""
    devnull = open(os.devnull, 'w')
    retcode = subprocess.call(['which', prog], stdout=devnull)
    devnull.close()
    return retcode == 0


def check():
    available_cmd = None
    for cmd in KCACHEGRIND_EXECUTABLES:
        if is_installed(cmd):
            available_cmd = cmd
            break

    if available_cmd is None:
        sys.stderr.write("Could not find %s\n"
                         % ", ".join(KCACHEGRIND_EXECUTABLES))
        return

if __name__ == '__main__':
    check()