Question

I’m sorting a text file from Python using a custom unix command that takes a filename as input (or reads from stdin) and writes to stdout. I’d like to sort myfile and keep the sorted version in its place. Is the best way to do this from Python to make a temporary file? My current solution is:

inputfile = "myfile"
# inputfile: filename to be sorted
tmpfile = "%s.tmp_file" %(inputfile)
cmd = "mysort %s > %s" %(inputfile, tmpfile)
# rename sorted file to be originally sorted filename
os.rename(tmpfile, inputfile)

Is this the best solution? thanks.

Answer 1

If you don’t want to create temporary files, you can use subprocess as in:

import sys
import subprocess

fname = sys.argv[1]
proc = subprocess.Popen(['sort', fname], stdout=subprocess.PIPE)
stdout, _ = proc.communicate()
with open(fname, 'w') as f:
    f.write(stdout)