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LukasRypl/logging and tracing.sh

Created October 25, 2016 15:58
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Log and debug -- without XDEBUGFD so it works with bash version <4.1
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logging and tracing.sh
#!/bin/bash -eu
tag=$(dirname $(readlink -f $0))/$(basename $0)
# redirects output to logger, -s print it to stderr as well, -t add script name as a tag
# http://stackoverflow.com/questions/3173131/redirect-copy-of-stdout-to-log-file-from-within-bash-script-itself
exec > >( logger -s -t "${tag} [INFO ]" )
# trap handler: print last error - filename, line, return code to stderr
function error-trap-handler()
{
FILENAME=$(dirname $(readlink -f $0))/$(basename $0)
# filanem handled by output redirections as well but it does not work for included files
LASTLINE="$1" # argument 1: last line of error occurence
LASTERR="$2" # argument 2: error code of last command
echo "${FILENAME} at line ${LASTLINE}: exit status of the last command: ${LASTERR}" >&2
}
# to print all commands with timestamps: export DEBUG=1
if [ "$DEBUG" == "1" ] ; then
echo "DEBUG MODE is ON!"
set -x
echo "Traps: "
trap -p
echo "Flags: $-"
export PS4='+ $(date "+%F %T") ${BASH_SOURCE}:${LINENO} ${FUNCNAME[0]:+${FUNCNAME[0]}(): }'
exec 2> >( logger -s -p user.debug -t "${tag} [DEBUG]" )
else
trap 'error-trap-handler ${LINENO} $?' ERR
# redirect std err
exec 2> >( logger -s -p user.err -t "${tag} [ERR ]" )
fi
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# If set, any trap on ERR is inherited by shell functions, command substitutions, 
# and commands executed in a subshell environment.
set -E

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