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- """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.]
- """
-
- # 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 == 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
-