Directory and Files.md

Directories & Files

Making a directory with mkdir

To make a new directory use mkdir as sudo mkdir directoryName

Changing directory with cd

To change a directory use the cd command as cd ./directoryName to go to a inner directory and to move to a parent directory use cd /directory like cd /Home to go Home or cd / to move to the previous one. See the below table for more info

Command	What it does
cd dirNm	Go to directory
cd or cd ~	Go to $HOME directory
cd ..	Go up a directory
cd -	Go to previous directory
pwd	Where am I - show current directory
ls	List contents of directory
ls -alh	What's here - list all files and folders
mkdir dir_name	Make a directory
sudo rm -r dir_name	Delete a directory and any files it contains

List the contents of directory with ls

To list the contents use ls ./directory you can also do ls ./directory1/directory2 to list the contents of a child directory whereas just typing ls will show the contents of current directory. You can also refer ~ for the home directory as ls ~/user/documents

Using nano

nano is a text editor that can be used to read/write files in the console, you can use sudo nano filename to open a file where the file is in current directory. To save a file press Ctrl+O and to exit nano Ctrl+X

Move/Rename file/folder with mv

Use the MV command to move a file or directory as sudo mv <currentPath/filename> <newPath/filename> Make sure the file/directory name is same else the mv command will rename the file/directory.

Command	What it does
rm somefilename.*	Remove file or files
mv {old-dir-name} {new-dir-name}	Move or rename file
cp existing_file.txt new_file.txt	Copy file
wget http://downloads.somedomain.com/...	Download file

Linux Directory Structure

Directory	Description
/	Primary hierarchy root and root directory of the entire file system hierarchy.
/bin	Essential command binaries that need to be available in single user mode; for all users, e.g., cat, ls, cp.
/boot	Boot loader files, e.g., kernels, initrd.
/dev	Essential device files, e.g., /dev/null.
/etc	Host-specific system-wide configuration files
/etc/opt	Configuration files for add-on packages that are stored in /opt.
/etc/sgml	Configuration files, such as catalogs, for software that processes SGML.
/etc/X11	Configuration files for the X Window System, version 11.
/etc/xml	Configuration files, such as catalogs, for software that processes XML.
/home	Users' home directories, containing saved files, personal settings, etc.
/lib	Libraries essential for the binaries in /bin and /sbin.
/lib<qual>	Alternate format essential libraries. Such directories are optional, but if they exist, they have some requirements.
/media	Mount points for removable media such as CD-ROMs (appeared in FHS-2.3 in 2004).
/mnt	Temporarily mounted filesystems.
/opt	Optional application software packages.
/proc	Virtual filesystem providing process and kernel information as files. In Linux, corresponds to a procfs mount. Generally automatically generated and populated by the system, on the fly.
/root	Home directory for the root user.
/run	Run-time variable data: Information about the running system since last boot, e.g., currently logged-in users and running daemons.
/sbin	Essential system binaries, e.g., fsck, init, route.
/srv	Site-specific data served by this system, such as data and scripts for web servers, data offered by FTP servers, and repositories for version control systems (appeared in FHS-2.3 in 2004).
/sys	Contains information about devices, drivers, and some kernel features.[7]
/tmp	Temporary files (see also /var/tmp). Often not preserved between system reboots, and may be severely size restricted.
/usr	Secondary hierarchy for read-only user data; contains the majority of (multi-)user utilities and applications.[8]
/usr/bin	Non-essential command binaries (not needed in single user mode); for all users.
/usr/include	Standard include files.
/usr/lib	Libraries for the binaries in /usr/bin and /usr/sbin.
/usr/lib<qual>	Alternate format libraries, e.g. /usr/lib32 for 32-bit libraries on a 64-bit machine (optional).
/usr/local	Tertiary hierarchy for local data, specific to this host. Typically has further subdirectories, e.g., bin, lib, share.[9]
/usr/sbin	Non-essential system binaries, e.g., daemons for various network-services.
/usr/share	Architecture-independent (shared) data.
/usr/src	Source code, e.g., the kernel source code with its header files.
/usr/X11R6	X Window System, Version 11, Release 6 (up to FHS-2.3, optional).
/var	Variable files—files whose content is expected to continually change during normal operation of the system—such as logs, spool files, and temporary e-mail files.
/var/cache	Application cache data. Such data are locally generated as a result of time-consuming I/O or calculation. The application must be able to regenerate or restore the data. The cached files can be deleted without loss of data.
/var/lib	State information. Persistent data modified by programs as they run, e.g., databases, packaging system metadata, etc.
/var/lock	Lock files. Files keeping track of resources currently in use.
/var/log	Log files. Various logs.
/var/mail	Mailbox files. In some distributions, these files may be located in the deprecated /var/spool/mail.
/var/opt	Variable data from add-on packages that are stored in /opt.
/var/run	Run-time variable data. This directory contains system information data describing the system since it was booted.In FHS 3.0, /var/run is replaced by /run; a system should either continue to provide a /var/run directory, or provide a symbolic link from /var/run to /run, for backwards compatibility.
/var/spool	Spool for tasks waiting to be processed, e.g., print queues and outgoing mail queue.
/var/spool/mail	Deprecated location for users' mailboxes.[12]
/var/tmp	Temporary files to be preserved between reboots.

Backup & Restore with dd

To backup a drive as img file

sudo dd if=/dev/sda of=backup.img bs=1M

To restore img file to drive

sudo dd bs=4M if=backup.img of=/dev/mmcblk0

if pv is installed you may use

dd bs=4M if=backup.img | pv | dd of=/dev/sda