pysedsh.py

#!/usr/bin/env python
# If Win32, MSYS/cygwin with sed is required

import sys

if __name__ != '__main__':
    print "This script must be run, not imported"
    sys.exit(1)

try:
    import readline
except ImportError:
    # readline not available :(
    pass

from subprocess import Popen, PIPE

_data = "abcdefghijklmnopqrstuvwxyz"

print
print
print "Python sed shell"
print
print "Any input is equivalent to the command:"
print
print "  echo '<data>' | sed -re '<regex>'"
print "where <regex> is the input as a Python expression"
print
print "To set <data>, use the function d(), like:"
print '  >> d("hello")'
print
print "To see <data>'s content, use the function d() without argument"
print
print "<data> defaults to %s" % _data
print
print

class DataSet(Exception):
    pass

def d(data=None):
    global _data

    if data is None:
        print _data
    else:
        _data = data

    raise DataSet()

def exit():
    sys.exit(0)

while True:
    try:
        regexp = input('>> ')
        if not isinstance(regexp, basestring):
            print '?'
            continue
        sed = Popen(['sed', '-re', regexp], stdout=PIPE, stdin=PIPE, stderr=PIPE)
        stdout, stderr = sed.communicate(_data)
        if sed.returncode == 0:
            print stdout
        else:
            print "! %s" % stderr
    except DataSet:
        continue
    except EOFError:
        break
    except KeyboardInterrupt:
        break
    except Exception, e:
        print "!! %s" % e.msg