Exit Codes & Exceptions
Normal processes exit with exit code 0. This can be seen from
RunningCommand.exit_code
:
output = ls("/", _return_cmd=True)
print(output.exit_code) # should be 0
If a process terminates, and the exit code is not 0, an exception is generated
dynamically. This lets you catch a specific return code, or catch all error
return codes through the base class ErrorReturnCode
:
try:
print(ls("/some/non-existant/folder"))
except ErrorReturnCode_2:
print("folder doesn't exist!")
create_the_folder()
except ErrorReturnCode:
print("unknown error")
You can also customize which exit codes indicate an error with _ok_code. For example:
for i in range(10):
sh.grep("string to check", f"file_{i}.txt", _ok_code=(0, 1))
where the _ok_code makes a failure to find a match a no-op.
Signals
Signals are raised whenever your process terminates from a signal. The exception raised in this situation is SignalException, which subclasses ErrorReturnCode.
try:
p = sh.sleep(3, _bg=True)
p.kill()
except sh.SignalException_SIGKILL:
print("killed")
Note
You can catch SignalException by using either a number or a signal name. For example, the following two exception classes are equivalent:
assert sh.SignalException_SIGKILL == sh.SignalException_9