Which command shows all of the directories that the shell searches for programs?

$PWD holds the current working directory, not the executable search path, so less $PWD would attempt to page through a directory listing, not show search paths.

echo $PATH expands the PATH environment variable and prints its value, which is the ordered list of directories the shell searches when resolving command names. This is the standard, built-in mechanism for inspecting the executable search path on any POSIX-compatible shell.

$ALL_PATH is not a standard shell environment variable and does not exist by default on any POSIX system.

get is not a standard shell built-in or common utility; no such command exists for printing environment variables.

cat reads file contents by path; $PATH expands to a string of directory names, so cat $PATH would attempt to open a file whose name is that string, not print the variable's value.