Fedora Linux

punctuation. Start the filename with a letter or digit (unless you want to specify a hidden file), and do not include spaces.

Although it makes command-line file manipulation more awkward, more and more users are adding spaces to photo and music filenames. 

? Use the single form of words instead of the plural ( font instead of fonts ); it's less typing, and you won't have to keep track of whether you chose the singular or plural form.

? Filename extensions (such as .gif , .txt , or .odt ) are not recognized by the Linux kernel; instead, the file contents and security permissions determine how a file is treated. However, some applications do use extensions as an indication of file type, so it's a good idea to employ traditional extensions such as .mp3 for MP3 audio files and .png for portable network graphics files.

4.3.1.5. Listing the contents of directories

The ls (list-directory-contents) command will display a list of the files in the current working directory:

$ ls
4Suite crontab hosts libuser.conf nxserver
a2ps.cfg cron.weekly hosts.allow lisarc oaf
...(Lines snipped)...

You can specify an alternate directory or file pattern as an argument:

$ ls /
bin etc lost+found mnt proc sbin sys usr
boot home media net ptal selinux tftpboot var
dev lib misc opt root srv tmp

$ ls -d a*

a2ps.cfg alsa ant.conf audit.rules
a2ps-site.cfg alternatives ant.d auto.master
acpi amanda asound.state auto.misc
adjtime amandates atalk auto.net
alchemist amd.conf at.deny auto.smb
aliases amd.net atmsigd.conf
aliases.db anacrontab auditd.conf

By default, filenames starting with a dot ( . ) are not shown. This provides a convenient way to store information such as a program configuration in a file without constantly seeing the filename in directory listings; you'll encounter many dot files and directories in your home directory. If you wish to see these 'hidden' files, add the -a (all) option:

$ ls -a

ls can display more than just the name of each file. The -l (long) option will change the output to include the security permissions, number of names, user and group name, file size in bytes, and the date and time of last modification:

$ ls -l
-rw------- 1 chris chris 3962 Aug 29 02:57 a2script
-rwx------ 1 chris chris 17001 Aug 29 02:57 ab1
-rw------- 1 chris chris 2094 Aug 29 02:57 ab1.c
-rwx------ 1 chris chris 884 Aug 29 02:57 perl1
-rw------- 1 chris chris 884 Aug 29 02:57 perl1.bck
-rwx------ 1 chris chris 55 Aug 29 02:57 perl2
-rw------- 1 chris chris 55 Aug 29 02:57 perl2.bck
-rwx------ 1 chris chris 11704 Aug 29 02:57 pointer1
-rw------- 1 chris chris 228 Aug 29 02:57 pointer1.c
-rwx------ 1 chris chris 12974 Aug 29 02:57 pp1
-rw------- 1 chris chris 2294 Aug 29 02:57 pp1.c

ls -l is so frequently used that Fedora has a predefined alias (shorthand) for it: ll. 

You can also sort by file size (from largest to smallest) using -S :

$ ls -S -l
-rwx------ 1 chris chris 17001 Aug 29 02:57 ab1
-rwx------ 1 chris chris 12974 Aug 29 02:57 pp1
-rwx------ 1 chris chris 11704 Aug 29 02:57 pointer1
-rw------- 1 chris chris 3962 Aug 29 02:57 a2script
-rw------- 1 chris chris 2294 Aug 29 02:57 pp1.c
-rw------- 1 chris chris 2094 Aug 29 02:57 ab1.c
-rwx------ 1 chris chris 884 Aug 29 02:57 perl1
-rw------- 1 chris chris 884 Aug 29 02:57 perl1.bck
-rw------- 1 chris chris 228 Aug 29 02:57 pointer1.c
-rwx------ 1 chris chris 55 Aug 29 02:57 perl2
-rw------- 1 chris chris 55 Aug 29 02:57 perl2.bck

The first character on each line is the file type: - for plain files, d for directories, and l for symbolic links.

There are dozens of options to the ls command; see its manpage for details.

4.3.1.6. Displaying and changing the current working directory

To print the name of the current working directory, use the pwd (print- working-directory) command:

$ pwd
/home/chris

To change the directory, use the cd (change-directory) command.

To change to the /tmp directory:

$ cd /tmp

To change to the foo directory within the current directory: