Explain errno numbers (QNX Neutrino)
The errno utility displays the string equivalent for the error_numbers supplied on the command line. The output is written to the standard output. If the command-line argument isn't a valid error number, a line is written to the standard error instead.
This utility is useful in cases where a program has indicated that a numerical error occurred and hasn't provided the ASCII string equivalent of that errno value. Users who don't have access to the C header file <errno.h> don't have the option of using:
grep error_number /usr/include/errno.h
The errno utility is more convenient and is available to all users.
Find the string equivalent of error number 2:
$ errno 2 errno 2: ERROR ENOENT $