I swear I have seen this done before but can not find it now. Is it possible to have a shell script start a python interpeter "mid stream", ie:
#!/bin/bash
#shell stuff..
set +e
VAR=aabb
for i in a b c; do
echo $i
done
# same file!
#!/usr/bin/env python
# python would be given this fd which has been seek'd to this point
import sys
print ("xyzzy")
sys.exit(0)
You can use this shell syntax (it is called here document in Unix literature):
#!/bin/sh
echo this is a shell script
python <<@@
print 'hello from Python!'
@@
The marker after '<<' operator can by an arbitrary identifier, people often use something like EOF (end of file) or EOD (end of document). If the marker starts a line then the shell interprets it as end of input for the program.
If your python script is very short. You can pass it as a string to python using the -c option:
python -c 'import sys; print "xyzzy"; sys.exit(0)'
Or
python -c '
import sys
print("xyzzy")
sys.exit(0)
'
You could write
exec python <<END_OF_PYTHON
import sys
print ("xyzzy")
sys.exit(0)
END_OF_PYTHON
to replace the Bash process with Python and pass the specified program to Python on its standard input. (The exec replaces the Bash process. The <<END_OF_PYTHON causes standard input to contain everything up till END_OF_PYTHON.)
env. I suppose the command could be exec env python <<END_OF_PYTHON, but it's probably better just to remove the shebang.Of course right after I posted this I remembered a way to do it:
#!/bin/sh
echo Shell
python <<EOF
import sys
print "Python"
sys.exit(0)
EOF
I agree that mixing/mashing up can be quite a powerful technique - not only in scripting but also in command line (e.g. perl inliners have been proven to be very successful over time). So my small tip on another variation of one-liners (in addition to mentioned by kev) for mixed scripting in bash/python:
for VAR in $(echo 'import sys; print "x y z"; sys.exit(0)' | python -);do echo "$VAR"; done;
produces
x
y
z
