Fedora™ Unleashed, 2008 edition

/initrd	Initial RAM disk boot support (used during boot time)
/lib	Shared libraries, kernel modules
/lost+found	Directory for recovered files (if found after a file system check)
/media	Mount point for removable media, such as DVDs and floppy disks
/mnt	Usual mount point for local, remote file systems
/opt	Add-on software packages
/proc	Kernel information, process control
/root	Super user (root home)
/sbin	System commands (mostly root only)
/selinux	Holds the data for SELinux, the security component of Fedora
/sys	Real-time information on devices used by the kernel
/tmp	Temporary files
/usr	Secondary software file hierarchy
/var	Variable data (such as logs); spooled files

Some of the important directories in Table 4.1, such as those containing user and root commands or system configuration files, are discussed in the following sections. You use and edit files under these directories when you use Fedora.

Linux also includes a number of GNU commands you can use to search the file system. These include the following:

> whereis command—Returns the location of the command and its man page.

> whatis command — Returns a one-line synopsis from the command's man page.

> locate file command — Returns locations of all matching file(s); an extremely fast method of searching your system because locate searches a database containing an index of all files on your system. However, this database (about 4MB in size and named slocate.db, under the /var/lib/slocate directory) is built daily at 4:20 a.m. by default, and does not contain pathnames to files created during the workday or in the evening. If you do not keep your machine on constantly, you can run the updatedb command as the super user to manually start the building of the database.

> apropos subject command — Returns a list of commands related to subject.

Managing Files with the Shell

Managing files in your home directory involves using one or more easily remembered commands. If you have any familiarity with the now-ancient DOS, you recognize some of these commands (although their names differ from those you remember). Basic file management operations include paging (reading), moving, renaming, copying, searching, and deleting files and directories. These commands include the following:

> cat filename — Outputs contents of filename to display

> less filename — Allows scrolling while reading contents of filename

> mv file1 file2 — Renames file1 to file2

> mv file dir — Moves file to specified directory

> cp file1 file2 — Copies file1 and creates file2

> rm file — Deletes file

> rmdir dir — Deletes directory (if empty)

> grep string file(s) — Searches through files(s) and displays lines containing matching string