Usage

Run command

Without the flag, you actually execute the command.

So

command node

is the same as just

node

This can be useful if you want to ignore any aliases or functions an execute the original version. For example if you defined

alias mv='mv -i

So this will run the alias

mv ARGS

And this will run the original builtin.

command mv ARGS

This works despite the fact that command -v mv tells you about the alias, not the original value.

You’ll get an error if it doesn’t exist.

$ command unknown
zsh: command not found: unknown

Get description

Add the -v flag, you get a description of the command.

command -v COMMAND

From help:

  -v print a description of COMMAND similar to the `type' builtin

It will print nothing if the command does not exist.

$ command -v unknown

Find binary

$ # Package
$ command -v node
/usr/local/bin/node

$ which node
/usr/local/bin/node

$ type node
node is /usr/local/bin/node

Find alias

$ command -v ll
alias ll='ls -lh'

$ which ll
ll: aliased to ls -lh

type ll
ll is an alias for ls -lh

Examples

$ command -v node
/usr/local/bin/node

Check if package exists

Execute logic depending on if a system package is installed.

This will hide any output and errors and use the exit status to check if the target could be found or not.

if ! command -v node >/dev/null 2>&1;
  # Install node ...
fi

if command -v node >/dev/null 2>&1; then
  node -v
else
  # Install node ...
fi