You can use heredoc if you want to keep the source of both bash and python scripts together. For example, say the following are the contents of a file called pyinbash.sh:
#!/bin/bash
echo "Executing a bash statement"
export bashvar=100
cat << EOF > pyscript.py
#!/usr/bin/python
import subprocess
print 'Hello python'
subprocess.call(["echo","$bashvar"])
EOF
chmod 755 pyscript.py
./pyscript.py
Now running the pyinbash.sh will yield:
$ chmod 755 pyinbash.sh
$ ./pyinbash.sh
Exe
The simplest approach is to just save the python script as, for example script.py and then either call it from the bash script, or call it after the bash script:
#!/usr/bin/env bash
echo "This is the bash script" &&
/path/to/script.py
Or
script.sh && script.py
#!/bin/bash
# Here are some embedded Python examples using Python3.
# They are put into functions for separation and clarity.
# Simple usage, only using python to print the date.
# This is not really a good example, because the `date`
# command works just as well.
function date_time {
python3 - <<END
from datetime import datetime
print('Current date:')
print(datetime.now())
END
}
# Call the python code.
date_time
# Sending a variable to Python from BASH
function env_args {
# Put an environment arg into Python.
# Must be on the same line as the command.
TESTARG="My Value" python3 - <<END
from os import environ
print('Your environment arg: {}'.format(environ.get('TESTARG', 'missing!')))
END
}
env_args
# Retrieve output from Python and put it into a BASH variable.
# This uses a subshell to retrieve whatever python prints out.
function val_from_python {
# Get a python value from BASH.
pythonval="$(python3 - <<END
import os
print('cwd: {}'.format(os.getcwd()))
END
)"
echo "Python value is: $pythonval"
}
val_from_python
# You can put small python snippets directly into your shell files.
# Here's an example using `urllib` to download some html, and then
# using it in BASH.
# (granted that you could do this in Python itself,
# or you could write it all in BASH, but this is just an example.)
function python_power {
# Grab the html from python.org's PEP8 page and save it to a bash variable.
# On error, the output will be a basic HTML page with the error message.
local pythonval="$(python3 - <<END
from urllib import request
try:
resp = request.urlopen('http://legacy.python.org/dev/peps/pep-0008/')
data = resp.read().decode('utf-8')
print(data)
except Exception as ex:
print("""
<html>
<head>
<title>Error in python_power</title>
</head>
<body>
There was an error retrieving that page: {}
</body>
""".format(ex))
END
)"
# Print the content so it can be used by other commands.
# (you also could've saved it to a global variable.)
echo $pythonval
}
# Direct the output of this python function to a file.
# The html will not be styled correctly, because no css files are downloaded.
# But the point here is that you can have the full power of python without
# writing separate scripts. Small python snippets can be embedded and used
# from BASH itself.
outfile='pep8.html'
python_power > $outfile
if [[ -f $outfile ]]; then
echo "New file was created: $outfile"
google-chrome $outfile
else
echo "Unable to create new file: $outfile"
fi
*2 Example of the dangers of temp files. DO NOT USE THIS CODE
cat >/tmp/python-script <<END
for i in range(10):
print(i)
END
python /tmp/python-script
If someone else creates /tmp/python-script first, this shell script won't even stop if it fails to overwrite the file. A malicious user on the system could make a harmful Python script which will run instead of the intended script.
There are ways to do this safely, but the simplest way would be to create the files in the current working directory or in a dedicated directory in the home directory.
cat >dopythonstuff <<END
...
END
python dopythonstuff
rm dopythonstuff
Just pass a HereDoc to python -.
From python help python -h:
- : program read from stdin
#!/bin/bash
MYSTRING="Do something in bash"
echo $MYSTRING
python - << EOF
myPyString = "Do something on python"
print myPyString
EOF
echo "Back to bash"
You can use heredoc if you want to keep the source of both bash and python scripts together. For example, say the following are the contents of a file called pyinbash.sh:
#!/bin/bash
echo "Executing a bash statement"
export bashvar=100
cat << EOF > pyscript.py
#!/usr/bin/python
import subprocess
print 'Hello python'
subprocess.call(["echo","$bashvar"])
EOF
chmod 755 pyscript.py
./pyscript.py
Now running the pyinbash.sh will yield:
$ chmod 755 pyinbash.sh
$ ./pyinbash.sh
Exe