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