Linux Training Online – Using the Linux CD Command to Change Directory – Linux System Administration

As a new user looking for Linux training, you need to learn how to use commands. And one of the most commonly used file system commands is the CD (change directory) command.

Using the Linux CD Command

The CD (change directory) command is used to change from your current directory (folder) into a different directory.

You need to change into a directory to do Linux administration tasks like:

  • create a new file or remove an existing file
  • copy or move a file to a different directory
  • edit and modify a file, such as a text configuration file for a Linux server
  • create a new directory or remove an existing directory
  • copy or move a directory to a different directory

Linux Commands Training Tips: The System Administration commands, examples and concepts covered here apply to ALL Linux distributions, including: Red Hat, Fedora, Ubuntu, Edubuntu, Kubuntu, Slackware, Debian, SUSE and openSUSE.

Linux CD Command Example – Changing into a Directory Below the Current Directory

To change directory into a directory “below” the current one, you type in CD and a space and the name of the directory you want to change into.

For example, to change into a directory named “letters”, you run the following:

$ CD letters

To change into a different directory, just replace “letters” with a different name.

Linux Training Tips: A directory inside the current one is considered “below” the current directory, and is called a sub directory.

Linux CD Command Example – Changing Up One Directory (Level)

To change directory up one directory (level), you type in CD and a space and then two dots (periods).

For example, if you have moved into the directory named “letters” and want to go back (up) to your previous directory, you run the following:

$ CD ..

Linux Training Tips: The directory above the current one is also called the “parent”.

Beyond This “Linux Training Online” ArticleThe Linux CD command is used in many other ways to navigate around the file system.

To continue your Linux training, you also need to learn how to use the CD command to: change to the root directory, change using an absolute path, and also easily change into a directory parallel to the current directory.

You can clearly and easily see all of the concepts and commands shown above (and lots more!) by watching a Linux training video.

With this method of Linux training, you can see how to use a command step-by-step and also hear how to run the command. This is a very easy way to learn how to use Linux.

Understanding Linux Hard Disk Partitioning and Linux File Systems – System Administration Training

The Linux Hard Disk Partitioning Process

A hard disk is partitioned and then it is assigned a filesystem type and then it is formatted.

Assigning a filesystem type to a partition specifies the “type” of it and prepares (formats) it so that it can accept files.

Do not confuse assigning a filesystem “type” with assigning a filesystem (formatting).

Linux Hard Disk Partitioning – File Systems and Filesystem Types

Most Linux documentation and utilities refer to a file system as filesystem (one word).

A filesystem type is assigned to and specified for a partition to provide it with support for the file structure of itself (for its directories and subdirectories) and for all of the files that will be used on it, such as the Linux program files and data files.

For example, the current default filesystem type for many distributions, such as Red Hat, Fedora and others, is ext3 (extended filesystem 3).

Prior to ext3, the default filesystem was ext2 (extended filesystem 2). Some other distributions have a different default filesystem, but ext3 is on the way to becoming the de facto standard for Linux.

Linux Hard Disk Partition “Rules”

A Linux partition can be all or part of a hard disk.

If you have two hard disks in a system, then one disk can have one partition, filesystem type and operating system on it that uses the entire disk and the other disk can have a different set of these items, that uses the entire disk.

Both disks can also have more than one partition, filesystem type and operating system.

If you only have one Linux hard disk in a system, then you can create two or more partitions on the disk, assign each one a different filesystem type and install a different operating system on each.

A partition cannot contain more than one filesystem type and does not typically contain more than one operating system. However, you can have a single OS on a system that uses multiple filesystem types on multiple partitions (one filesystem type per partition).

The “standard” Windows and Linux operating systems require at least one partition each. If a system requires both of these operating systems, then you need at least one partition for each of them.

The Linux hard disk partitioning concepts and commands covered here apply to: Red Hat, Fedora, Slackware, Ubuntu, and Debian Linux – and ALL other versions.

Understanding Linux Filesystems & Linux Filesystem Types – Linux System Admin Training – Run Ubuntu

The Default Linux File Systems (Filesystems)

The default filesystems that are recognized by Linux are specified in the text file named filesystems in the /proc directory.

Four of the filesystems that are commonly found on a Linux system are: ext2 (old and less common), ext3 (very common), iso9660 and swap.

Some Linux distributions also use other filesystems.

For example, instead of the ext3 filesystem, the SUSE and openSUSE distributions use the reiserfs filesystem by default.

In addition to the above filesystems, by default Linux can also recognize a partition that is a “swap” partition.

Depending on the documentation that you are reading and the command or utility that you are using, “swap” is not typically considered to be a filesystem type. It is a type of partition that is treated by the OS as virtual memory (where hard disk storage space works as though it is RAM memory).

The following is a description of some of the commonly used Linux filesystems.

ext2 (second extended filesystem) supports UNIX/Linux files and directories and allows for long file names (up to 255 characters).

ext3 (third extended filesystem) is the current default filesystem for Red Hat, Fedora and many other Linux distributions. The ext3 filesystem is on the way to becoming the de facto standard for Linux.

ext3 is based on the previous ext2 filesystem. It is basically the same as ext2, with the main difference being that ext3 supports a feature called “journalling”. The greatest benefit of this feature is that it provides a quicker recovery when a filesystem “crash” occurs and a system goes “down” (and stops working).

If files are corrupted on a partition using ext2, then the Linux fsck (filesystem check) utility is run to check the filesystem and repair it and this can take a very long time.

When the files on an ext3 filesystem become corrupted, then the fsck utility is still run to check and repair the filesystem, but this takes much less time due to the journalling feature of ext3.

vfat is the Linux filesystem that is compatible with DOS file names and Windows long file names. In some Linux utilities, “vfat” appears as “fat” or “fat32”.

iso9660 is the filesystem used on a CD-ROM.

swap (a.k.a. Linux swap partition, swap drive, swap space) is a disk partition that is used by the Linux OS as “virtual memory”. Linux uses the disk space that you have specified for the swap drive as though it were RAM (memory chips in your system).

The Linux filesystem type concepts and definitions covered here apply to: Ubuntu, Debian, Red Hat, Fedora, SUSE, Slackware, openSUSE – and ALL other Linux distributions.