Interpreting \ escape sequences in strings

[Peter Otten]

Paul Watson wrote:

> How can I get the escapes from a command line parameter interpreted?
> 
> The user provides a string on the command line.  The string might contain
> traditional escapes such as \t, \n, etc.  It might also contain escaped
> octal or hex such as \001 or \x09.
> 
> The escapes are coming into sys.argv[] without shell interpretation.  Do I
> need to use the compile module to make this work?  Any suggestions?
> 
> ===
> $ cat ./try_arglen2.py
> #! /usr/bin/env python
> import sys, StringIO
> print sys.argv[1]
> 
> print sys.argv[1] % ()
> 
> sf = StringIO.StringIO()
> print >> sf, sys.argv[1],
> c = sf.getvalue()
> sf.close()
> print "now" + c + "is" + c + "the"
> 
> # This works because the interpreter is processing the escapes.
> 
> sf = StringIO.StringIO("\001")
> c = sf.getvalue()
> sf.close()
> print "now" + c + "is" + c + "the"
> 
> ===
> $ ./try_arglen2.py '\001'
> \001
> \001
> now\001is\001the
> now?is?the

If I'm understanding you correctly:

<args.py>
import sys
print sys.argv[1].decode("string_escape")
</args.py>

$ python args.py "winter\nof\012our\x0Adiscontent"
winter
of
our
discontent

Peter