"""Execute shell commands via os.popen() and return status, output. Interface summary:        import commands        outtext = commands.getoutput(cmd)       (exitstatus, outtext) = commands.getstatusoutput(cmd)       outtext = commands.getstatus(file)  # returns output of "ls -ld file" A trailing newline is removed from the output string. Encapsulates the basic operation:       pipe = os.popen('{ ' + cmd + '; } 2>&1', 'r')      text = pipe.read()      sts = pipe.close()  [Note:  it would be nice to add functions to interpret the exit status.]""" __all__ = ["getstatusoutput","getoutput","getstatus"] # Module 'commands'## Various tools for executing commands and looking at their output and status.## NB This only works (and is only relevant) for UNIX.  # Get 'ls -l' status for an object into a string#def getstatus(file):    """Return output of "ls -ld <file>" in a string."""    return getoutput('ls -ld' + mkarg(file))  # Get the output from a shell command into a string.# The exit status is ignored; a trailing newline is stripped.# Assume the command will work with '{ ... ; } 2>&1' around it..#def getoutput(cmd):    """Return output (stdout or stderr) of executing cmd in a shell."""    return getstatusoutput(cmd)[1]  # Ditto but preserving the exit status.# Returns a pair (sts, output)#def getstatusoutput(cmd):    """Return (status, output) of executing cmd in a shell."""    import os    pipe = os.popen('{ ' + cmd + '; } 2>&1', 'r')    text = pipe.read()    sts = pipe.close()    if sts is None: sts = 0    if text[-1:] == '\n': text = text[:-1]    return sts, text  # Make command argument from directory and pathname (prefix space, add quotes).#def mk2arg(head, x):    import os    return mkarg(os.path.join(head, x))  # Make a shell command argument from a string.# Return a string beginning with a space followed by a shell-quoted# version of the argument.# Two strategies: enclose in single quotes if it contains none;# otherwise, enclose in double quotes and prefix quotable characters# with backslash.#def mkarg(x):    if '\'' not in x:        return ' \'' + x + '\''    s = ' "'    for c in x:        if c in '\\$"`':            s = s + '\\'        s = s + c    s = s + '"'    return s