This is a quick tips and tricks guide to using the command line.
The filesystem has a number of conventions for file names.
- Paths are separated by forward slash
/. .means the current directory...means the directory above the current one.~is your home directory.- File names that begin with a period
.are hidden by default. *is a glob, which you can use as a wildcard in paths.**is a recursive glob (descends multiple levels).
The "shell" is the program you interact with, where you type commands. The "terminal emulator" is the window that you launch in your window manager. "Terminal" is used generally to refer to whole thing. Most Linux distributions use bash as the default login shell. OSX is starting to use zsh. This guide references bash config .bashrc, but the same applies to the config file for zsh confige .zshrc.
Historical terminology is to call the "Option"/"Alt" key on a standard keyboard "Meta", and the "Windows"/"Command" key "Super". "Control" is still "Control".
You will sometimes see a control sequence written as "^s", which means hold control and type the s key. "^S" often means hold shift as well (i.e. type a capital S).
Other source will write "C-s" and "C-S" for command and "M-s" for meta prefix.
Follow the instructions to set "Option as Meta key". https://support.apple.com/guide/terminal/change-profiles-keyboard-settings-trmlkbrd/mac
The command line can seem slow. Typing out everything is slow. The folks who designed the tools made them to be as efficient as possible. The tab key is your best friend. Everytime you hit tab, the shell will attempt to autocomplete. If there are multiple possible completions, it will complete as much as it can and show you all the options. Type a few more characters and the tab again. When you are changing directories, you do not have to change one directory, list the contents of the directory, then change directory again. Just add a slash, and then keep using autocomplete..
Previous commands you've executed are still available. If you need to repeat a command or fix a mistake, you can use "C-p" or the up arrow to go back through history. If you need to rerun a previous command further back in history, use "C-r" to do a reverse search back through history.
The key to efficiency is to minimize movement. Every time you take your hands off the keyboard, you slow yourself down. If you reach over to the mouse, the arrow keys, or the navigation keys, you are wasting time. Standard command line tools support the following key shortcuts (among many others). These are also available in the editor Emacs, which along with vim are the gold standard for text editing in Unix environments. The same principle applies in other programs you use, especially your IDE. Learn the keyboard shortcuts!
Using the command line will be slow at first. You will be tempted to reach for the arrow keys or the mouse. Deliberate practice is required, so take the time to learn the habits you need.
- C-n: go to the next command in history
- C-p: go to previous command in history
- C-r: reverse search back through history
- M-.: cycle through previous arguments (I got nothing for a mnemonic)
- C-f: move cursor forward one character
- C-b: move cursor back one character
- M-f: forward one word
- M-b: move back one word
- C-a: move to beginning of line (a is on the far the left side of the keyboard, just like the beginning of the line.)
- C-e: move to end of line
- C-d: delete char forward
- M-d: delete word forward
- M-del: delete word backwards
- C-k: delete (kill) from cursor to end of line
- M-u: make uppercase
- M-c: make first letter capital
- M-1: make lowercase
- C-c cancels the current process
You can create aliases to common commands to simplify your workflow. In any shell session, you can create an alias for any command.
alias piconfig='cmake -B build -S .'
alias pibuild='cmake --build build
alias piflash='picotool -f build/src/something.elf'
alias g=git
alias py=python3
If you want to use an alias across sessions, you can add them to your ~/.profile or ~/.bashrc file.
You can create aliases for git as well.
In ~/.gitconfig you can put aliases (among other useful config). In my configuration I have the following aliases.
[pretty]
treeline= %C(bold blue)%h%C(reset) %C(yellow)%ai%C(reset) %C(white)%s%C(reset) %C(dim white)- %an%C(reset)%C(bold yellow)%d%C(reset)
[alias]
co = checkout
br = branch
ci = commit
st = status
mt = mergetool
dt = difftool
rb = rebase
mg = merge
sm = submodule
praise = blame
tree = log --graph --all --abbrev-commit --decorate --pretty=treeline
treehere = log --graph --abbrev-commit --decorate --pretty=treeline
root = rev-parse --show-toplevel
On my terminal, with shell and git aliases I run git status with g st.
Everything goes in source control, even your config. Create a folder (I use .dotfiles) to store all your configuration (the "dot files"). From your home directory, create symlinks to the config (e.g. ln -s .dotfiles/.bashrc). Whenever you setup on a new computer, you just have to clone your config and link. Config changes are easy to move between machines.
Just don't forget to commit and push when you make changes.
The real power of the shell is that you work in a full programming environment! Common constructs like loops, variables, conditionals, and more are at your fingertips. You can put a set of commands into a script file for repeated execution. The syntax may be a bit different from what you find in C, but isn't too hard to pick up. You don't need to learn it all at once - as you need to use a feature, look up the syntax.
Any good Unix hacker has a prompt setup to maximize their productivity.
You can set up a decent one if you use Bash by putting the following in your ~/.bashrc file.
PROMPT_COMMAND='PS1_CMD1=$(__git_ps1 " (%s)")'; PS1='\t \u@\h [\w]${PS1_CMD1} \$'
You can go nuts with generating a custom prompt.
If you get the following error, you will need to setup the PATH environment variable.
% foo
bash: foo: command not found
PATH is a colon (:) separated list of locations the shell will search when you provide a command. It might look something like this.
PATH=/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
You can list currently set environment variables with the env command.
If a program is installed in a location not in your PATH, you can add the location in your ~/.bashrc or ~/.profile configuration.
export PATH=$PATH:/home/snelgrov/.pico-sdk/toolchain/13_2_Rel1/bin