This command will fail with non-zero status upon error. Some exit
codes are:
-- The config file is invalid (ret=3),
-- can not write to the config file (ret=4),
+- The section or key is invalid (ret=1),
- no section or name was provided (ret=2),
-- the section or key is invalid (ret=1),
+- the config file is invalid (ret=3),
+- the config file cannot be written (ret=4),
- you try to unset an option which does not exist (ret=5),
- you try to unset/set an option for which multiple lines match (ret=5), or
- you try to use an invalid regexp (ret=6).
You can override these rules either by command-line options or by environment
variables. The '--global' and the '--system' options will limit the file used
-to the global or system-wide file respectively. The GIT_CONFIG environment
+to the global or system-wide file respectively. The `GIT_CONFIG` environment
variable has a similar effect, but you can specify any filename you want.