Help command can help you understand any built-in commands in linux/unix. For newcomers to the Linux/Unix operating system, if you encounter trouble using the built-in commands, we can use the help command to view its help manual.
Demo environment Mac os
help [-s] [pattern ...]
Display helpful information about builtin commands. If PATTERN is specified, gives detailed help on all commands matching PATTERN, otherwise a list of the builtins is printed. The -s option restricts the output for each builtin command matching PATTERN to a short usage synopsis.
In the following example, the help command is used to display the help manual of the cd command.
bash-3.2$ help cd
Use the help -s option to display only the syntax of the command.
bash-3.2$ help -s cd
cd: cd [-L|-P] [dir]
Demo environment Ubuntu os
help [-dms] [pattern ...]
-d output short description for each topic
-m display usage in pseudo-manpage format
-s output only a short usage synopsis for each topic matching PATTERN
PATTERN Pattern specifying a help topic
Use -s: This option is only used when you only want to understand the syntax of the command.