2) The Linux Filesystem and commands

1. The Linux Filesystems

2. Introduction to some Linux bash commands

1. The Linux Filesystem

The Linux file system can intended in two ways: the directories tree that describes the file organization/structure and the format that defines how files are stored on disk (FAT32, ext4, etc). In this class, we will talk about the default layout of the directories tree on a Linux system.

Tip

Check this very useful resource on The Linux Filesystem

Directory	Description
/	Root directory of the entire file system
/bin	Essential command binaries needed for single-user mode
/boot	Boot loader files (e.g., kernels)
/dev	Device files (e.g., keyboard, mouse, etc; convenient to back up)
/etc	Specific system-wide configuration files
/home	Users’ home directories, containing saved files, personal settings, etc.
/lib	Libraries essential for binaries in /bin and /sbin
/media	Mount points for removable media (e.g., CD-ROMs)
/mnt	Temporarily mounted file systems
/opt	Add-on application software packages (e.g., Word Procs, Accounting soft, etc.)
/root	Home directory for the root user
/run	Information about the running system since last boot
/sbin	Essential system binaries (e.g., fsck equivalent to Windows CHKDSK)
/srv	Site-specific data served by the system (e.g., Web servers data and scripts, etc.)
/sys	Information about devices, drivers, some kernel features
/tmp	Temporary files (usually not preserved between system reboots)
/usr	Secondary hierarchy for read-only user data (e.g., multi-user utilities and applications)
/var	Files whose context is expected to continually change during normal operation of the system (e.g., logs, spool files, etc.)

2. Some basic Linux commands

Tip

Check this very useful resource on Linux command line for beginners

Command	Meaning
Ctrl l	Clean screen (keeps command history)
reset	Initialize terminal
Ctrl A	Move cursor to the beginning of command line
Ctrl E	Move cursor to the end of command line
ls	List current working directory content
ls -l	List permission strings and other info
ls -t	Sort files and directories by their last modification time (most recently modified first)
ls *.txt	List all files with txt extension
ls -al	List all files (including hidden files)
ls -l /	List files in root directory
pwd	Print current working directory
cd /	Change working directory to root
cd ..	Change working directory one level up
cd -	Get back to previous directory
cd ~	Short hand for your home directory
mkdir <dir_name>	Create new directory dir under current directory
mkdir {dir1,...,dirN}	(no spaces) Create new directories dir1, … , dirN under current dir
mkdir -p dir1/dir2/dir3	Create a parent directory dir1/dir2/dir3 (three levels deep)
rm file1 ... fileN	Remove files file1, …, fileN
rm -r dir	Remove directory dir and its content recursively
mv	Move or rename existing files/directories
cat file1 ... fileN	Concatenate files file1,…,fileN and print result
touch file1 ... fileN	Create empty files or edit existing file
./<command>	Execute a local command/program/script
chmod file	Change file permissions
man <command>	See documentation of any <command>

Exercise 2.1

Print the current working directory

Tip

If you want to use any shell commands in your Julia Jupyter notebook, you can simply change the mode of the Julia REPL by prepending ; to your command.

Exercise 2.2

Create a new directory and move into it

Exercise 2.3

Now that you have created a directory, initialize a git repository (Exercise 1.1. from last class)

Exercise 2.4

Delete the newly created directory