Set Up Bash Dotfiles

.bashrc, .bash_profile, .bash_aliases

Check if you have a ~/.bashrc file.

ls ~/.bashrc

Now you need to decide to use ~/.bash_aliases or ~/.bashrc. The .bash_aliases is usually plenty and doesn’t interfere with what the system thinks you should use for .bashrc. In fact, sometimes you don’t even have permission to change it (as is the case with PicoCTF). However, sometimes changing the .bashrc gives you more control. Consider doing that later. You can always use the same dotfiles/bashrc file and put it into ~/.bash_aliases if you are on a system that does not allow you to change it (again, like PicoCTF).

Peek at ~/.bashrc to See if ~/.bash_aliases Sourced Change into your dotfiles project repo directory Make a bash directory Make a new bashrc file (no initial period) Create a symlink from ~/.bashrc to the bashrc

ln -fs "$PWD/bashrc" "$HOME/.bashrc"

Confirm the creation of the symlink.

file ~/.bashrc

Resetting Your Shell

Before we do much more it is important to know how to get your Bash configuration to reset. You could certainly close your terminal and reopen it, or log back in, but the fastest way is simply to use the exec command as follows:

exec bash

This works even better if one of the first things in your bashrc file is a command to clear everything that was set before. Otherwise the new shell inherits all the environment from the previous shell and only changes those things that are new. This means that anything you have removed will still be there.

To clear everything from the previous settings consider unsetting all your aliases.

unalias -a

Now you can start building the rest of your custom bashrc file.

Adding Aliases

First off let’s add an alias.

How about making an alias for clear.

Open the bashrc file for editing.

alias c=clear

Now test it by resetting your shell.

exec bash

How about we add an alias with spaces requiring quotes. We’ll use single quotes because they are easier to type.

alias ll='ls -la'

Now reset and test that one.

Okay, looks like everything is working.

You might want to take a moment and make a comment for the section about aliases so that you can find it fast later is it grows longer.

Now for some more important stuff.

set -o vi

Reset and test that your arrow keys still work. Vi mode means that you are effectively in --INSERT-- mode when working with your history as if it were a big file, except you can only see one line. This is why your arrow keys work but not your hjkl navigation keys.

You activate command mode by pressing Esc or the Control-[ equivalent.

Now can do anything to your history as if it were a large file you are working with in Vi command mode. This includes searching through your entire history with / and then finding the next occurrence with n or previous with N. Notice that n continuously wraps around with the search. This is really fast way to pull up complex lines from your history that you did weeks ago.

Configure Your Shell Command History

Now is probably a good time to add more capacity to your history file, or remove it if you are on an ultra-secure system.

Type history to get a sample of your history. You will probably have a hundreds of lines. Do it again and pipe the output to less if you want to see them all.

Your history is actually saved in a ~/.bash_history file that you can reset at any time. Some people even preserve it in their dotfiles but that is probably not a good idea considering how much it changes.

Let’s up the size of the history from the default of about 500.

Commonly the following environment variables are set related to history:

HISTCONTROL=ignoreboth  # don't save dups and starting with spaces
  HISTFILESIZE=10000      # how many lines to save

You can learn more about them by searching for them in the Bash manual page. There are many other settings related to history you can set.