How do I use homebrew less instead of system less?

Question

I've installed less via

homebrew install less

but less starts the system version of less, not the one installed via homebrew. which less shows:

$ which -a less
/usr/local/bin/less
/usr/bin/less

where /usr/local/bin/less is a symlink to ../Cellar/less/487/bin/less (homebrew less) and /usr/bin/less is the system less. echo $LESS returns nothing. How can I start homebrew less instead of system less by default?

Answer 1

This might be due to bash's hash table of commands in PATH still using the old value. Remove the hash of less, or clear the hash, so that bash re-searches PATH:

hash -d less
# or, hash -r

You can also manually add a path to the table:

hash -p /usr/local/bin/less less

From the Bash manual (emphasis mine):

If the name is neither a shell function nor a builtin, and contains no slashes, Bash searches each element of $PATH for a directory containing an executable file by that name. Bash uses a hash table to remember the full pathnames of executable files to avoid multiple PATH searches (see the description of hash in Bourne Shell Builtins). A full search of the directories in $PATH is performed only if the command is not found in the hash table.

Answer 2

If homebrew is correctly installed /usr/local/bin/ is checked before /usr/bin/. Check this with echo $PATH, this will show you the path's the OS is trying to find the command you entered and it is trying them in the order that is shown.

A little fancier
using the bash shell:

echo $PATH | awk '{ n = split($0, paths, ":"); for (i=0; ++i <= n;) print i, paths[i] }'

(using the fish shell):

echo $PATH | awk '{ n = split($0, paths, " "); for (i=0; ++i <= n;) print i, paths[i] }'

This will show an numbered list of the path's tried. Mine shows

1 /Users/peter/.gem/ruby/2.0.0/bin
2 /usr/local/sbin
3 /usr/local/bin
4 /usr/bin
5 /bin
6 /usr/sbin
7 /sbin
8 /Library/TeX/texbin

The system will traverse the directories in the above order looking for commands, in your case less. If it's not in the first one, it will try the next one until it runs out of options and throw up an error.

So if your echo $PATH shows similar results as mine you are using the homebrew version of less.

Answer 3

I restarted the shell, and this fixed the problem. Maybe a caching issue.

If this doesn't help, make sure that /opt/homebrew/bin appeares above /usr/bin when running

echo $PATH | tr ':' '\n' | nl`