Major changes
- 'check_status_re' and therefore 'runpipe_re' use 'grep -E'
instead of 'grep' in order to simplify regexp that
contains >=2 digit exit statuses.
NOTE: Formally speaking this breaks backward compatibility.
- If PIPESTATUS_VERBOSE variable is set to non-empty string, then
check_status0 and check_status_re functions print an error
message to stderr.
to obtain an exit status of every program in a pipe.
MOTIVATION
When we program in shell we often run pipes like this
prog1 args1 | prog2 args2 | ... | progN argsN
POSIX says that exit status of pipe is the exit status of LAST program
in it, i.e. progN in our example. That is, exit status of all other
programs in pipe is silently ignored. But in many situations exit
status of all programs in pipe should be checked to make program
robust. Some shells like BASH and ZSH have special extensions for
doing this but POSIX shell unfortunately doesn't provide an EASY way
for doing this.
In order to solve the problem, described above pipestatus was written.
