[bash] Bash foreach loop

I have an input (let's say a file). On each line there is a file name. How can I read this file and display the content for each one.

cat `cat filenames.txt`

will do the trick

Here is a while loop:

while read filename
do
    echo "Printing: $filename"
    cat "$filename"
done < filenames.txt

xargs --arg-file inputfile cat

This will output the filename followed by the file's contents:

xargs --arg-file inputfile -I % sh -c "echo %; cat %"

If they all have the same extension (for example .jpg), you can use this:

for picture in  *.jpg ; do
    echo "the next file is $picture"
done

(This solution also works if the filename has spaces)

You'll probably want to handle spaces in your file names, abhorrent though they are :-)

So I would opt initially for something like:

pax> cat qq.in
normalfile.txt
file with spaces.doc

pax> sed 's/ /\\ /g' qq.in | xargs -n 1 cat
<<contents of 'normalfile.txt'>>
<<contents of 'file with spaces.doc'>>

pax> _

"foreach" is not the name for bash. It is simply "for". You can do things in one line only like:

for fn in `cat filenames.txt`; do cat "$fn"; done

Reference: http://www.cyberciti.biz/faq/linux-unix-bash-for-loop-one-line-command/