Foundation (FSF). URL: http://www.stallman.org/
One Day One Command
strace — Trace System Calls and Signals.
In the simplest case strace runs the specified command until it exits.
It intercepts and records the system calls which are called by a
process and the signals which are received by a process. The name of
each system call, its arguments and its return value are printed.
strace is a useful diagnostic, instructional, and debugging tool.
$ strace sleep 1 — Trace all Sys call of ‘sleep’ command.
$ strace ls — Trace all Sys call of ‘ls’ command.
$ strace -i sleep 1 — Print the value of the Instruction Pointer at
every sys call.
$ strace -r sleep 1 — Print a relative time-stamp with each line of
$ strace -t sleep 1 — Prefix each line of the trace with the time of
$ strace -T sleep 1 — Show time spent on each call.
$ strace -o file sleep 1 — Redirect the output to a file.
$ strace -c ls — Count time, calls, and errors for each system call
and report a summary on program exit.
$ strace -xx myprg — Print all strings in HEX format.
$ strace -e trace=file ls — Trace all system calls which take a
filename as an argument.
$ strace -e trace=process ls — Trace all system calls which involve
$ sleep 60 & — Dummy background Job.
$ strace -p 1234 — Attach to the process with the PID 1234 (use
dummy job’s Pid) and trace.
Read: man strace