Using apple's Automator to pass filenames to a shell script.

Question

I have an automator script that I'd like to run on a folder. I want the script to take each file in the folder and run my shell command on it. Automator is set to pass input to stdin, but I don't think I'm using stdin correctly below, can you help please?

for f in "$@" 
do
    java -Xmx1000m -jar /Users/myprog/myprog.jar $f 
done

Answer 1

Sorry, I just realized it worked as pass input as argument instead of as stdin, I'm not sure why though? If you can explain that would be great. Thanks.

Answer 2

The special variable $@ represents all the command-line arguments provided to the script.

The for loop steps through each one and executes the jar file each time. You could shorten the script to:

for f
do
    java -Xmx1000m -jar /Users/myprog/myprog.jar "$f"
done

since the default behavior of for is to use $@.

You should put quotes around $f at the end of the java command in case there are spaces in the arguments.

Answer 3

I'm not sure I understand your question since your script does not appear to be using stdin. The $@ special parameter expands to the positional parameters passed as arguments in argv. It works the same way as if you called the script directly from the shell this way:

$ cat >test
for f in "$@"
do
  echo $f
done
$ chmod 755 test
$ ./test a b c
a
b
c

If you wanted to get the arguments from stdin, you could do something like this:

$ cat >test2
for f in $(cat)
do
  echo $f
done
$ chmod 755 test2
$ ./test2 <<EOF
> a b c
> EOF
a
b
c