How can I print a Python file's docstring when executing it?
The docstring is stored in the module's __doc__
global.
print(__doc__)
By the way, this goes for any module: import sys; print(sys.__doc__)
. Docstrings of functions and classes are also in their __doc__
attribute.
Here is an alternative that does not hardcode the script's filename, but instead uses sys.argv[0] to print it. Using %(scriptName)s instead of %s improves readability of the code.
#!/usr/bin/env python
"""
Usage: %(scriptName)s
This describes the script.
"""
import sys
if len(sys.argv) < 2:
print __doc__ % {'scriptName' : sys.argv[0].split("/")[-1]}
sys.exit(0)
Argument parsing should always be done with argparse
.
You can display the __doc__
string by passing it to the description
parameter of Argparse:
#!/usr/bin/env python
"""
This describes the script.
"""
if __name__ == '__main__':
from argparse import ArgumentParser
parser = ArgumentParser(description=__doc__)
# Add your arguments here
parser.add_argument("-f", "--file", dest="myFilenameVariable",
required=True,
help="write report to FILE", metavar="FILE")
args = parser.parse_args()
print(args.myFilenameVariable)
If you call this mysuperscript.py and execute it you get:
$ ./mysuperscript.py --help
usage: mysuperscript.py [-h] -f FILE
This describes the script.
optional arguments:
-h, --help show this help message and exit
-f FILE, --file FILE write report to FILE