Pyle makes it easy to use Python as a replacement for command line tools such as sed or perl. For instance, to perform an in-place string substitution, overwriting the original file with the updated file, you might do:
pyle -ie "re.sub(r'alien(s|)?', r'ghost\1', line)" TextAboutAliens.md
To print the first 20 characters of each line of a file:
cat README.md | pyle -e "line[:20]"
or:
pyle -e "line[:20]" README.md
Pyle imports the (sh)[https://pypi.python.org/pypi/sh] module by default, which allows running child commands easily.
List all /tmp/ files with a filename with an even length:
ls /tmp/ | pyle -e "sh.ls('-l', line) if len(line) % 2 == 0 else None"
In addition to line, a list called words is also available which is the current line split by whitespace. To print just the URLs in an Apache access log (the seventh "word" in the line):
tail access_log | pyle -e "words[6]"
Print the SHA 256 sum of each *.py file in the current directory:
$ ls *.py | pyle -m hashlib -e "'%s %s' % (hashlib.sha256(line).hexdigest(), line)"
348e4a65e24bab4eed8e2bbe6f4c8176ddec60051d1918eea38b34b1103a8af6 pyle.py
b28c7f73e6df990a96cfb724be1d673c2d3c43f68d4b6c06d8e5a9b29e5d12cb pyle_test.py
If your expression returns a list or a tuple, the items will be printed joined by spaces. With that in mind we can simplify the above example:
$ ls *.py | pyle -m hashlib -e "(hashlib.sha256(line).hexdigest(), line)"
348e4a65e24bab4eed8e2bbe6f4c8176ddec60051d1918eea38b34b1103a8af6 pyle.py
b28c7f73e6df990a96cfb724be1d673c2d3c43f68d4b6c06d8e5a9b29e5d12cb pyle_test.py
Print the first five lines of each file with filenames and line numbers:
$ pyle -e "'%-15s:%04d %s' % (filename, 1 + num, line) if num < 5 else None" *.py
The idea for Pyle is based on Graham Fawcett's PyLine. Pyle is mostly compatible with PyLine but requires a -e before the evaluation statement.
pip install pyle
Some of us are just simply awful at remembering the sed, perl or even bash syntax but feel right at home with Python. Python code is often a little more verbose but what good is saving characters if you can't remember what they do?
Here's an example of sed vs pyle. This isn't a very good sed expression, admittedly, but the people who will find Pyle useful are not sed experts.
To change home directories from /var/X to /home/X:
sed 's/^\(\([^:]*:\)\{5\}\)\/var\/\(.*\)/\1\/home\/\3/g' /etc/passwd
pyle -e "re.sub(r'^(([^:]*:){5})/var/(.*)', r'\1/home/\3', line)" /etc/passwd
If you find the Python code more readable, Pyle is for you.
This file and pyle --help.
Free to use and modify under the terms of the BSD open source license.