My shellscript template

shellscript-template.sh

#!/bin/bash

set -Cu
set -Ee
set -o pipefail
shopt -s nullglob

stime=$(date +%Y%m%d%H%M%S%Z)
based=$(readlink -f $(dirname $0)/..)
pname=$(basename $0)

exec 3>&2
# logd=$based/log
# exec 3>&2 2>$logd/$pname.$stime.$$.log
# set -vx

MSG() {
    echo "$pname pid:$$ stime:$stime etime:$(date +%Y%m%d%H%M%S%Z) $@"	>&3
}

tmpd=$(mktemp -d -t "$pname.$stime.$$.XXXXXXXX")/
if [ 0 -ne "$?" ] ; then
    MSG "line:$LINENO FATAL can not make temporally directory."
    exit 1
fi

trap 'BEFORE_EXIT' EXIT
BEFORE_EXIT()	{
    rm -rf $tmpd
}

trap 'ERROR_HANDLER' ERR
export EMSG="line:$LINENO ERROR"
ERROR_HANDLER()	{
    MSG "line:$LINENO ERROR status ${PIPESTATUS[@]}"
    [ "$EMSG" ] && MSG $EMSG
    touch $tmpd/ERROR	# for child process error detection
    MSG "line:$LINENO EXIT with error."
    exit 1		# root process trigger BEFORE_EXIT function
}

PROGRESS() {
    lineno="$1"
    shift
    PMSG="$*"
    MSG "line:$lineno INFO $PMSG"
    EMSG="line:$lineno ERROR while $PMSG"
}

################################################################
PROGRESS "$LINENO" "testing script"

MSG "line:$LINENO INFO This is a message."

EMSG="line:$LINENO FATAL unreachable."
true

EMSG="line:$LINENO INFO while forking child process."
(
    EMSG="line:$LINENO INFO child process 1 error"
    true | false | true
)	&

(
    set +o pipefail
    EMSG="line:$LINENO INFO child process 2 error"
    true | false | true
)	&

EMSG="line:$LINENO INFO while waiting child process."
wait
[ ! -e $tmpd/ERROR ]

################################################################
PROGRESS "$LINENO" "exiting"
shopt -u nullglob
MSG "line:$LINENO EXIT without error."
exit 0