example of its use: $ date | ./a.out out.log | cat ... cat out.log Tue Oct 28 10:06:00 CET 2014 Program source #define _GNU_SOURCEline arguments supplied to our example program: $ cat /tmp/key_instantiate.log Time ... with the name mykey and ID 20d035bf . $ cat /proc/keys | egrep 'mykeyschedulers currently loaded in the kernel: $ cat /sys/block/sda/queue/scheduler noop anticipatory deadline [cfq] The scheduler surroundedschedulers currently loaded in the kernel: $ cat /sys/block/sda/queue/scheduler noop anticipatory deadline [cfq] The scheduler surroundedarchitecture: $ uname -m x86_64 $ syscall_nr() { cat /usr/src/linux/arch/x86/syscalls/syscall_64.tbl | \ awk '$2 != "x32" && $3 == "'$1'" { printscript whose "interpreter" is our myecho program: $ cat > script #!./myecho script-arg ^D $ chmodCPUID bit, like with the following command: cat /proc/cpuinfo | grep ' mpx ' A thread