bash: redirect (and append) stdout and stderr to file and terminal and get proper exit status
Another possibility, with some bash
flavours, is to turn on the pipefail
option:
pipefail
If set, the return value of a pipeline is the value of the last (rightmost) command to exit with a non-zero status, or zero if all commands in the pipeline exit successfully. This option is disabled by default.
set -o pipefail...command 2>&1 | tee -a file.txt || echo "Command (or tee?) failed with status $?"
This having been said, the only way of achieving PIPESTATUS
functionality portably (e.g. so it'd also work with POSIX sh
) is a bit convoluted, i.e. it requires a temp file to propagate a pipe exit status back to the parent shell process:
{ command 2>&1 ; echo $? >"/tmp/~pipestatus.$$" ; } | tee -a file.txtif [ "`cat \"/tmp/~pipestatus.$$\"`" -ne 0 ] ; then ...fi
or, encapsulating for reuse:
log2file() { LOGFILE="$1" ; shift { "$@" 2>&1 ; echo $? >"/tmp/~pipestatus.$$" ; } | tee -a "$LOGFILE" MYPIPESTATUS="`cat \"/tmp/~pipestatus.$$\"`" rm -f "/tmp/~pipestatus.$$" return $MYPIPESTATUS}log2file file.txt command param1 "param 2" || echo "Command failed with status $?"
or, more generically perhaps:
save_pipe_status() { STATUS_ID="$1" ; shift "$@" echo $? >"/tmp/~pipestatus.$$.$STATUS_ID"}get_pipe_status() { STATUS_ID="$1" ; shift return `cat "/tmp/~pipestatus.$$.$STATUS_ID"`}save_pipe_status my_command_id ./command param1 "param 2" | tee -a file.txtget_pipe_status my_command_id || echo "Command failed with status $?"...rm -f "/tmp/~pipestatus.$$."* # do this in a trap handler, too, to be really clean
There is an arcane POSIX way of doing this:
exec 4>&1; R=$({ { command1; echo $? >&3 ; } | { command2 >&4; } } 3>&1); exec 4>&-
It will set the variable R
to the return value of command1
, and pipe output of command1
to command2
, whose output is redirected to the output of parent shell.