What are commands to find shell keywords, built in functions and user defined functions?

You can also use compgen in bash:

• compgen -k lists keywords
• compgen -b or enable lists builtins
• compgen -A function or declare -F lists functions
• compgen -a or alias lists aliases
• compgen -c lists commands
• compgen -v lists variables
• compgen -e or export lists exported variables

With zsh:

PATH= type -m '*'

Will tell you all 3.

In bash, to list the keywords, you can do:

complete -A keyword :

and then type : <Tab><Tab>

For builtins, replace keyword with builtin above and for functions, I'll let you guess.

In Bash:

1. man bash | grep -10 RESERVED lists reserved words:

   ! case coproc do done elif else esac fi for function if in select then until while { } time [[ ]]

2. declare -F and typeset -F shows function names without their contents.

3. enable lists builtin shell commands (I don't think these are functions as such).So does man builtins