Open a file or pipe in the Perl style
from perl_io import PerlIO
Example 1:
pio = PerlIO('/proc/meminfo') # open /proc/meminfo for input
Example 2:
pio = PerlIO('> /tmp/foo.txt') # open '/tmp/foo.txt' for output
Example 3:
pio = PerlIO('>> /tmp/foo.txt') # open '/tmp/foo.txt' for appending
Example 4:
pio = PerlIO('| cmd arg1 ...') # we pipe output to the command `cmd'
Example 5:
pio = PerlIO('cmd arg1 ... |') # execute `cmd' that pipes output to us
You can access the Python file object as pio.fo after
PerlIO object pio was successfully created. pio.fo is set
to None if PelIO failed to open a file or pipe.
Example6:
Read the output of strings /usr/bin/python from a pipe
with PerlIO('strings /usr/bin/python |') as pio:
for line in pio.fo.xreadlines():
#
# do something...
#
Example7: Write to a file
with PerlIO('>/tmp/.tmpfile-%d' % (os.getpid())) as pio:
print >> pio.fo, 'This is an example'
pio.fo.write('This is another example')
pio.fo.write('\n')
###Note: PerlIO parses the parameter as follows in the case it indicates to input from or output to a pipe.
- Strips the first or last '|' (which indicates to open a pipe)
- If the remaining string includes shell special characters
like '|', '>', ';', etc.,
PerlIOcallsPopen()withsh -c 'remaining_string', which means it can be a security hazard when the remaining string includes the unsanitized input from an untrusted source. - If the remaining string includes no shell special characters,
PerlIO does not invoke shell when it calls
Popen().
###How to test: python -m unittest -v perl_io