Embedding Python in a shell script
Jason Friedman
#!/bin/bash
for i in 1 2 3 4; do
python -c "
for j in range($i):
print j
"
done
$ sh test.sh
0
0
1
0
1
2
0
1
2
3
The code behaves as I expect and want, but the de-denting of the
Python call is unattractive, especially unattractive the longer the
Python call becomes. I'd prefer something like:
$ cat test.sh
#!/bin/bash
for i in 1 2 3 4; do
python -c "
for j in range($i):
print j
"
done
But that yields:
$ sh test.sh
File "<string>", line 2
for j in range(1):
^
IndentationError: unexpected indent
File "<string>", line 2
for j in range(2):
^
IndentationError: unexpected indent
File "<string>", line 2
for j in range(3):
^
IndentationError: unexpected indent
File "<string>", line 2
for j in range(4):
^
IndentationError: unexpected indent
I realize I can create a "call_me.py" and do:
$ cat test.sh
#!/bin/bash
for i in 1 2 3 4; do
python call_me.py $i
done
but for various reasons I want a single script. Any alternatives?
Chris Angelico
> The code behaves as I expect and want, but the de-denting of the
> Python call is unattractive, especially unattractive the longer the
> Python call becomes. I'd prefer something like:
>
#!/bin/bash
for i in 1 2 3 4; do
python -c "if True:
for j in range($i):
print j
"
done
Untested, but it's a hack I've used in a few places. The if tells
Python to expect an indent, and nobody cares if your first indent is
two miles and the one after that is only another two spaces.
ChrisA
rusi
> > Python call becomes. I'd prefer something like:
>
> #!/bin/bash
> for i in 1 2 3 4; do
> python -c "if True:
# comfortably indented python code
Thanks. Nice!
mg
> On Jun 17, 6:05ï¿œam, Chris Angelico <ros...@gmail.com> wrote:
>
>> > Python call becomes. ï¿œI'd prefer something like:
>>
>> #!/bin/bash
>> for i in 1 2 3 4; do
> # comfortably indented python code
>
> Thanks. Nice!
You can use bash here document feature, <<-, that strips heading tab
characters but not spaces.
#!/bin/bash
for i in 1 2 3 4; do
python /dev/stdin <<-EOF
for i in range($i):
print i # two tabs and four spaces
EOF
done
Or alternatively you can use a temporary file:
#!/bin/bash
TEMPFILE=$(mktemp)
trap 'rm -f $TEMPFILE' TERM INT
cat > $TEMPFILE <<EOF
import sys
for i in range(int(sys.argv[1])):
print i
EOF
for i in 1 2 3 4; do
python $TEMPFILE $i
done
Timo Lindemann
>
> but for various reasons I want a single script. Any alternatives?
you can use a here document like this:
#! /bin/bash
/usr/bin/python2 << EOPYTHON
def hello():
print("Hello, World");
if __name__ == "__main__":
hello();
EOPYTHON
Hans Mulder
That does not solve the problem as stated. The OP wants to call python
inside a loop and he wants to indent things properly:
#!/bin/bash
for i in 1 2 3 4 5
do
python << EOPYTHON
def hello():
print("Hello, World");
if __name__ == "__main__":
hello();
EOPYTHON
done
That doesn't work, because the EOPYTHON token is indented.
If you put the EOPYTHON token flush left, it still doesn't work, because
Python does not accept indentation on line 1:
File "<stdin>", line 1
def hello():
^
IndentationError: unexpected indent
For some ideas that may work, read the earlier posts in this thread.
-- HansM
Timo Lindemann
> On 17/06/11 19:47:50, Timo Lindemann wrote:
>> On Fri, 17 Jun 2011 00:57:25 +0000, Jason Friedman said:
>>
>>
>>
>>> but for various reasons I want a single script. Any alternatives?
>>
>> you can use a here document like this:
> That does not solve the problem as stated. The OP wants to call python
> inside a loop and he wants to indent things properly:
so, wrap it inside a bash function like this:
#! /bin/bash
call_python() {
/usr/bin/python2 << EOPYTHON
def hello():
print("Hello, World $1");
if __name__ == "__main__":
hello();
EOPYTHON
}
for i in 1 2 3 4 5 6
do
call_python $i
done
That way, the indentation on is nicer; passing parameters to the script
inside the heredoc might be mean if the parameters are formed
difficultly, like, causing syntax errors if it's something like '"' or
somesuch. Probably beside the point though.
> For some ideas that may work, read the earlier posts in this thread.
maybe my news server doesn't fetch the whole thread. I didnt see any
replies, and still don't except yours.
Nice evenin'
-T.
Jason Friedman
decide which I like best.