^^&&^^

Edit File: strace-log-merge

#!/bin/sh
#
# This script processes strace -ff -tt output.  It merges the contents of all
# STRACE_LOG.PID files and sorts them, printing result on the standard output.
#
# Copyright (c) 2012-2018 The strace developers.
#
# SPDX-License-Identifier: LGPL-2.1-or-later

show_usage()
{
	cat <<__EOF__
Usage: ${0##*/} STRACE_LOG

Finds all STRACE_LOG.PID files, adds PID prefix to every line,
then combines and sorts them, and prints result to standard output.

It is assumed that STRACE_LOGs were produced by strace with -tt[t]
option which prints timestamps (otherwise sorting won't do any good).
__EOF__
}

dd='$[0-9][0-9]$'
ds='$[0-9][0-9]*$'

if [ $# -ne 1 ]; then
	show_usage >&2
	exit 1
elif [ "$1" = '--help' ]; then
	show_usage
	exit 0
fi

logfile=$1

for file in "$logfile".*; do
	[ -f "$file" ] || continue
	suffix=${file#"$logfile".}
	[ "$suffix" -gt 0 ] 2> /dev/null ||
		continue
	pid=$(printf "%-5s" $suffix)
	# Some strace logs have last line which is not '\n' terminated,
	# so add extra newline to every file.
	# grep -v '^$' removes empty lines which may result.
	sed -n "s/^$$dd:$\?$$dd:$\?$$ds\.$\?$ds /\2\4\6\7 $pid \0/p" < "$file"
	echo
done \
| sort -s -n -k1,1 | sed -n 's/^[0-9][0-9]* //p'

rc=$?
[ $rc -eq 1 ] &&
	echo >&2 "${0##*/}: $logfile: strace output not found"
exit $rc