BASH: how to read from piped stdout

[xyz000]

Hi,

I'd like to read some output from a console app, prepend some text and write the modified text to stdout. CTRL-C can be used to stop the operation. So suppose I have a text file (e.g. a README) like this:

Here is
some text

I want to be able to type this:

cat README | ./prepend-with-foo

to get this:

FOO: Here is
FOO: some text

I've tried the following script but "cat ./README | ./prepend-with-foo" doesn't work; it writes many lines of "FOO:" but nothing else. Any ideas?

#!/bin/bash
while [ 1 ]; do
  read FROM_STDIN
  echo "FOO: $FROM_STDIN"
done

[Manko10]

Your script actually does output your STDIN but it's too fast that you could notice that. You have to exit the loop as soon as no line is left:

while [ 1 ]; do
        read FROM_STDIN
        if [[ ! -n $FROM_STDIN ]]; then
                break
        fi 
        echo "FOO: ${FROM_STDIN}"
done

But

cat README | ./prepend-with-foo

is a candidate for the Useless Use of Cat Award.
Just use

./prepend-with-foo < ./README

But I wonder why you write your own script instead of using some tool like sed.

[barbus]

sed  -e 's/^/FOO /g' ./README