How to display all the unix commands available on the system?

Question

I'm reading a book, Learning Unix for OS X by Dave Taylor. It says:

To quickly see all of the binary executables—Unix programs—on your system,

Open the Terminal, hold down the Shift key, and press Esc-?, or press Control-X followed by Shift-1 (using Shift-1 to get an exclamation mark).

Before the commands are displayed in the Terminal, however, you’ll first be prompted (asked) to make a choice:

$ 
Display all 1453 possibilities? (y or n)

If you press the n key on your keyboard, you’ll be taken back to a command prompt and nothing else will happen. However, if you press the y key, you’ll see a multi-column list of Unix commands stream past in the Terminal window.

However, the problem is, when I hold down Shift key and press Esc-? nothing happens. Same for Pressing Control-X followed by Shift-1. What am I doing wrong? Is there any setting that I need to enable before using this feature? I'm using iTerm2 on Mac El Capitan. It doesn't work on the stock terminal either. Any help would be much appreciated. Thank you.

Answer 1

The instructions in the book are for bash. Zsh is a different program with different key bindings.

In zsh, you can see a list of all commands (external, builtin, function, alias even keywords...) with:

type -m '*'

For just their names:

whence -wm '*' | sed 's/:[^:]*$//'

Or for the names of external commands only:

print -rlo -- $commands:t | less

$commands is an array that contains all external commands. The history modifier :t truncates the directory part of the command paths (keeps only the tail). print -rlo to print them raw in alphabetical order, one per line.

Longer, but less cryptic:

for p in "$path[@]"; do (cd ${p:-.} && ls); done | sort -u | less

This can be adjusted to work in any sh-style shell:

(IFS=:; for p in $PATH; do (cd ${p:-.} && ls); done) | sort -u | less

(All the commands I list here assume that there are no “unusual” characters in command paths.)

Answer 2

Though pressing TAB twice will do the trick as mentioned by Thomas.

But if that didn't work then try this simple yet dirty hack:

for i in `echo $PATH | sed 's:\:: :g'`
do
       echo $i
done

Later, you can alter the view as per the need/ease.

Answer 3

Thanks to answer by @Gilles I figured out that the commands described in the question are for bash shell.

For bash users

So for future visitors, if you are using bash shell, refer to the commands described in the question description above to display all the available Unix commands on your system.

For zsh users

If you are using the zsh shell, the correct way to display all commands is:

Type ! (exclamation character) and press Tab key twice.

That is, press Shift + 1 and then press Tab key twice.

If this doesn't work for you, refer to tricks described by Gilles and SHW in other answers.