Bash is a Unix shell and command language written by Brian Fox for the GNU Project. in Ubuntu, one can use Ctrl + Alt + T to open a bash shell. In a bash shell, we use man command_name to get help information related to a command, use CTRL-C to break a program and CTRL-D to exit a shell or an REPL.
The bash grammar is well summarized in this cheatsheet. The following is a short list for commands that will be used in this course.
man # an interface to the system reference manuals
ls # list directory contents
cd # change directory
mkdir # make directories
rm # remove files or directories
pwd # print name of current/working directory
echo # display a line of text
cat # concatenate files and print on the standard output
alias # create an alias for a command
lscpu # display information about the CPU architecture
lsmem # list the ranges of available memory with their online status
top # display Linux processes
ssh # the OpenSSH remote login client
vim # Vi IMproved, a programmer's text editor
git # the stupid content tracker
useradd # create a new user or update default new user information
passwd # change user password
tar # an archiving utilityA more detailed cheat sheet and a lecture are available online.
SSH is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution. To learn more about SSH and two factor authentication, please check this lecture.
With a host name (the IP of the target machine to login) and a user name, one can use the following command to login,
ssh <username>@<hostname>You will get logged in after inputting the password.
A vim editor can be found in any Linux distribution, with or without a graphical user interface. To edit a file, just type vim file_name.
i # input
:w # write
:q # quit
:q! # force quit without saving
u # undo
CTRL-R # redoAll the commands must be executed in the command mode (the default mode when you start a vim editor), If you are currently in the input mode, you can alway type ESC to go back to the command mode.
To learn more about Vim, please check this lecture.
Git is a tool for version control. It is an important tool for programmers to keep track of the different versions of a program and collaborate with others. GitHub is a website and cloud-based service that helps developers store and manage their code, as well as track and control changes to their code. There are more than 100 git sub-commands, and the following is a short list to keep in mind.
# global config
git config # Get and set repository or global options
# initialize a repo
git init # Create an empty Git repo or reinitialize an existing one
git clone # Clone repository into new directory
# info
git status # Show the working tree status
git log # Show commit logs
git diff # Show changes between commits, commit and working tree, etc
# work on a branch
git add # Add file contents to the index
git rm # Remove files from the working tree and from the index
git commit # Record changes to the repository
git reset # Reset current HEAD to the specified state
# branch manipulation
git checkout # Switch branches or restore working tree files
git branch # List, create, or delete branches
git merge # Join two or more development histories together
# remote synchronization
git remote # Manage set of tracked repositories
git pull # Fetch from and integrate with another repo or a local branch
git fetch # Download objects and refs from another repository
git push # Update remote refs along with associated objectsA more detailed introduction could be found in this lecture.
MIT online course missing semester.