xargs with multiple arguments

Question

I have a source input, input.txt

a.txt b.txt c.txt 

I want to feed these input into a program as the following:

my-program --file=a.txt --file=b.txt --file=c.txt 

So I try to use xargs, but with no luck.

cat input.txt | xargs -i echo "my-program --file"{} 

It gives

my-program --file=a.txt my-program --file=b.txt my-program --file=c.txt 

But I want

my-program --file=a.txt --file=b.txt --file=c.txt 

Any idea?

Answer 1

Don't listen to all of them. :) Just look at this example:

echo argument1 argument2 argument3 | xargs -l bash -c 'echo this is first:$0 second:$1 third:$2' 

Output will be:

this is first:argument1 second:argument2 third:argument3 

Answer 2

None of the solutions given so far deals correctly with file names containing space. Some even fail if the file names contain ' or ". If your input files are generated by users, you should be prepared for surprising file names.

GNU Parallel deals nicely with these file names and gives you (at least) 3 different solutions. If your program takes 3 and only 3 arguments then this will work:

(echo a1.txt; echo b1.txt; echo c1.txt;  echo a2.txt; echo b2.txt; echo c2.txt;) | parallel -N 3 my-program --file={1} --file={2} --file={3} 

Or:

(echo a1.txt; echo b1.txt; echo c1.txt;  echo a2.txt; echo b2.txt; echo c2.txt;) | parallel -X -N 3 my-program --file={} 

If, however, your program takes as many arguments as will fit on the command line:

(echo a1.txt; echo b1.txt; echo c1.txt;  echo d1.txt; echo e1.txt; echo f1.txt;) | parallel -X my-program --file={} 

Watch the intro video to learn more: http://www.youtube.com/watch?v=OpaiGYxkSuQ