strace

A system call tracer
strace is a system call tracer, i.e. a debugging tool which prints out
a trace of all the system calls made by a another process/program.
The program to be traced need not be recompiled for this, so you can
use it on binaries for which you don't have source.
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System calls and signals are events that happen at the user/kernel
interface. A close examination of this boundary is very useful for bug
isolation, sanity checking and attempting to capture race conditions.