strace_log_merge

#!/bin/sh
#
# TODO: install alongside strace on "make install" time?

if test $# = 0; then
	echo "Usage: ${0##*/} STRACE_LOG"
	echo
	echo "\
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).\
"
	exit
fi

is_numeric() {
	# Remove digits. If something remains,
	# then $1 is not a number

	u=$1
	test "$u" || return 1 # "" is not a number

	while true; do
		v=${u#[0123456789]} # remove one digit
		test "$v" || return 0 # we removed all chars. ok
		test "$v" = "$u" && return 1 # we have non-digit. bad
		u=$v
	done
}

logfile=$1
pfxlen=${#1}

for file in "$logfile".*; do
	suffix=${file:1+$pfxlen}
	is_numeric "$suffix" || {
		echo "Skipped file '$file' (bad suffix)" >&2
		continue
	}
	pid=$(printf "%-5s" $suffix)
	# Some strace logs have last line which is not '\n' terminated.
	# 's/$/\n/' adds extra newlines to every line.
	# grep -v '^$' removes empty lines which may result.
	sed -e "s/^/$pid /" -e 's/$/\n/' <"$file"
done \
| grep -v '^$' | sort -k2