Exit Codes

Here are some common exit codes that may be returned by a program or script.

Status	Description
0	Successful Termination
1	General Error, typical catch-all value
2	Misuse of shell builtins, keywords, or functions
6	No such device or address. Eg. curl on an invalid host.
124	Command timed out (coreutils/timeout)
125	Command failure (coreutils/timeout)
126	Command found, but cannot be executed
127	Command not found. Possible path or typo issue.
128	Invalid argument to exit. Eg. `exit 1.1` would result in 128.
128+n	Fatal error signal n, where n is the signal number as defined in: https://man7.org/linux/man-pages/man7/signal.7.html
130	Program Interrupted (SIGINT, 128+2), such as termination from Ctrl-C
134	Program Abort (SIGABRT, 128+6)
136	Erroneous Arithmetic Operation (SIGFPE, 128+8), such as division by zero
137	Killed. (SIGKILL, 128+9)
139	Segmentation Fault (SIGSEGV, 11)
160+n	The largest signal value is 31. As a result, all values after 128+31 can be interpreted as negative return codes by treating the value as a 1 byte integer. For example, 255 = -1, 254 = -2, 240 = -16, 225 = -31, and so forth A simple way to 'convert' it is to just subtract the value from 256.
255	Maximum exit code value. Obtained when the program calls `exit -1`.
256+	All higher exit codes should be reduced down to the 0-255 range. More information below. You typically either modulo the code by 256 or take the high 8-bit values. Eg. Code `3809 % 256` results in 225, or code `32512 & 0xff00 >> 8` results in 127.

Parsing high exit code values

At least on Linux (and whatever is reported by Slurm), the exit code that's stored is an 2 byte value which can be parsed as:

Bits	Description
high 8 bits	The actual exit code
7 bit	if a core dump was produced
lower 7 bits	signal number that killed the process

For example, the exit code 32512 has an exit code of 127 (command not found).