Useful UNIX commands

This is my list of less known but great UNIX command I use daily.

It’s mostly focused on development rather than sysadmin.

ag

Super fast code search (grep on steroids).

$ ag ster
_posts/2016-11-11-useful-commands.md
73:Super fast code search (`grep` on steroids).

It will save you from the end of the world.

tree

Renders a folders and files hierarchy.

Example:

tree

$ tree
.
├── Gemfile
├── Gemfile.lock
├── LICENSE.md
├── README.md
├── Rakefile
├── _config.yml
├── _drafts
│   ├── from-linux-to-bsd.md
│   ├── react-redux-structure.md
│   └── using-normaliz-loki.md
├── _includes
│   ├── footer.html
│   ├── head.html
│   └── header.html
├── _layouts
│   ├── default.html
│   ├── page.html
│   └── post.html
...

On macOS, you can install it with hombrew.

direnv

Allows to have a local environment.

For example, if you put:

export MY_SECRET=hello

in a .envrc file, as soon as you cd <folder_containing_envrc> MY_SECRET will be defined to hello .

Super handy to manage app secrets.

pstree

Will display a tree of processes.

pstree -g 3 -w | less

Under FreeBSD, ps has a built in similar functionality:

ps -auxd | less

Piping into less is of course optional, but less is more.