Chris Tyler - Fedora Linux

To change to the /tmp directory:

$ cd /tmp

To change to the foo directory within the current directory:

$ cd foo

To change back to the directory you were in before the last cd command:

$ cd -

To change to your home directory:

$ cd

To change to the book directory within your home directory, regardless of the current working directory:

$ cd ~/book

To change to jason 's home directory:

$ cd ~ jason/

To create a directory from the command line, use the mkdir command:

$ mkdir newdirectory

This will create newdirectory in the current working directory. You could also specify the directory name using an absolute or relative-to-home pathname.

To create a chain of directories, or a directory when one or more of the parent directories might not exist, use the -p (path) option:

$ mkdir -p foo/bar/baz/qux

This has the side effect of turning off any warning messages if the directory already exists.

To delete a directory that is empty, use rmdir :

$ rmdir newdirectory

This will fail if the directory is not empty. To delete a directory as well as all of the directories and files within that directory, use the rm (remove) command with the -r (recursive) option:

$ rm -r newdirectory

rm -r can delete hundreds or thousands of files without further confirmation. Use it carefully!

To copy a file, use the cp command with the source and destination filenames as positional arguments:

$ cp /etc/passwd /tmp/passwd-copy

This will make a copy of /etc/passwd named /tmp/passwd-copy . You can copy multiple files with a single cp command as long as the destination is a directory; for example, to copy /etc/passwd to /tmp/passwd and /etc/hosts to /tmp/hosts :

$ cp /etc/passwd /etc/hosts /tmp

In Linux, renaming and moving files are considered the same operation and are performed with the mv command. In either cases, you're changing the pathname under which the file is stored without changing the contents of the file.

To change a file named yellow to be named purple in the current directory:

$ mv yellow purple

To move the file orange from jason 's home directory to your own:

$ mv ~jason/orange ~

The rm command will remove (delete) a file:

$ rm badfile

You will not be prompted for confirmation as long as you are the owner of the file. To disable confirmation in all cases, use -f (force):

$ rm -f badfile

Or to enable confirmation in all cases, use -i (interactive):

$ rm -i badfile

rm: remove regular empty file \Q

badfile

'?

y

-f and -i can also be used with cp and mv .

The graphical desktop tools don't directly delete files; they relocate them to a hidden directory named ~/.Trash , which corresponds to the desktop Trash icon, where they stay until the Empty Trash option is chosen. You can do the same thing from the command line:

$ mv badfile ~/.Trash

Linux systems store files by number (the inode number ). You can view the inode number of a file by using the -i option to ls :

$ ls -i /etc/hosts

3410634 /etc/hosts

A filename is cross-referenced to the corresponding inode number by a link and there's no reason why several links can't point to the same inode number, resulting in a file with multiple names.

This is useful in several situations. For example, the links can appear in different directories, giving convenient access to one file from two parts of the filesystem, or a file can be given a long and detailed name as well as a short name to reduce typing.

Links are created using the ln command. The first argument is an existing filename (source), and the last argument is the filename to be created (destination), just like the cp and mv commands. If multiple source filenames are given, the destination must be a directory.

For example, to create a link to /etc/passwd named ~/passwords , type:

$ ln /etc/passwd ~/passwords

The second column in the output from ls -l displays the number of links on a file:

$ ls -l electric.mp3

-rw-rw-r-- 1 chris chris 23871 Oct 13 01:00 electric.mp3

$ rm zap.mp3

$ ln electric.mp3 zap.mp3

$ ls -l electric.mp3

-rw-rw-r-- 2 chris chris 23871 Oct 13 01:00 electric.mp3

Although these types of links, called hard links , are very useful, they suffer from three main limitations:

 The target (file being linked to) must exist before the link is created.

 The link must be on the same storage device as the target.

 You cannot link to directories.

The alternative to a hard link is a symbolic link , which links one filename to another filename instead of linking a filename to an inode number. This provides a work-around for all three of the limitations of hard links.

The ln command creates symbolic links when the -s argument is specified:

$ ls -l ants.avi

-rw-rw-r-- 1 chris chris 1539071 Oct 13 01:06 ants.avi

$ ln -s ants.avi ants_in_ant_farm.avi

$ ls -l *ants*

-rw-rw-r-- 1 chris chris 1539071 Oct 13 01:06 ants.avi

lrwxrwxrwx 1 chris chris 8 Oct 13 01:06 ants_in_ant_farm.avi -> ants.avi

Notice that the the link count on the the target does not increase when a symbolic link is created, and that the ls -l output clearly shows the target of the link.

The file command will read the first part of a file, analyze it, and display information about the type of data in the file. Supply one or more filenames as the argument: