I've been trying to read a file in bash, and keep all the lines in a single variable, printing it at once after the loop:


all="EVIL_BASH"
cat /tmp/myfile | while read line; do
all="$all $line"
done
echo $all


However the output was only: EVIL_BASH, instead of having the lines of the /tmp/myfile appended.

WHAT THE HELL?

Because of the PIPE, the whole 'while' loop runs in another subshell. This means that $all outside the loop  is not the same $all from within the loop!

Sounds simply like scoping (as in perl), but a really awkward one. Beware.