/tmp>cat secret-keeper.c
#include <stdio.h>

int main(int argc, char ** argv)
{
        // note: security checks omitted
        fputs("find me, I'm the secret",stdout);
        return 0;
}

/tmp>make secret-keeper
cc     secret-keeper.c   -o secret-keeper

/tmp>strip secret-keeper

/tmp>cat secret-reader.pl
#!/usr/bin/perl

use strict;
use warnings;

my $secret=qx(./secret-keeper);
print "The secret is <$secret>\n";

/tmp>perl secret-reader.pl
The secret is <find me, I'm the secret>

/tmp>strace -o trace perl secret-reader.pl
The secret is <find me, I'm the secret>

/tmp>grep -C5 find trace /dev/null
trace-read(5, "", 4)                          = 0
trace-close(5)                                = 0
trace-ioctl(3, TCGETS, 0x7ffeddbf80a0)        = -1 ENOTTY (Inappropriate ioctl for device)
trace-lseek(3, 0, SEEK_CUR)                   = -1 ESPIPE (Illegal seek)
trace-fstat(3, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
trace:read(3, "find me, I'm the secret", 8192) = 23
trace-read(3, "", 8192)                       = 0
trace---- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=12034, si_uid=1001, si_status=0, si_utime=0, si_stime=0} ---
trace-fstat(3, {st_mode=S_IFIFO|0600, st_size=0, ...}) = 0
trace-close(3)                                = 0
trace-wait4(12034, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0, NULL) = 12034
trace:write(1, "The secret is <find me, I'm the "..., 40) = 40
trace-rt_sigaction(SIGHUP, NULL, {SIG_DFL, [], 0}, 8) = 0
trace-rt_sigaction(SIGINT, NULL, {SIG_DFL, [], 0}, 8) = 0
trace-rt_sigaction(SIGQUIT, NULL, {SIG_DFL, [], 0}, 8) = 0
trace-rt_sigaction(SIGILL, NULL, {SIG_DFL, [], 0}, 8) = 0
trace-rt_sigaction(SIGTRAP, NULL, {SIG_DFL, [], 0}, 8) = 0

/tmp>