help pages in linux

most CLI commands in Linux have helpful documention that you can pull up by adding -h or --help flags to the command

cd --help
pwd --help

# Typical output format:
Usage: cd [options] [directory]
Options:
  -L    force symbolic links to be followed
  -P    use the physical directory structure without following symbolic links
  ~     represents home directory
  ..    represents parent directory

Usage: pwd [OPTION]...
Print the current working directory
Options:
  -L    print the value of $PWD if it names the current working directory
  -P    print the physical directory, without any symbolic links