Linux Dummies 9th

Appendix A: Common Linux Commands
411
Command
compress
gunzip
gzip
tar
uncompress
unzip
zip
Purpose
Compresses files into .Z format. Pretty old and not used
much in the Linux world anymore.
Uncompresses .gz files and .tgz files.
Compresses files into .gz format.
Packages files together in a group called a tarball. The
most common way of using this command is tar xvf
filename, as in tar xvf download.tar.
Uncompresses files from .Z format.
Uncompresses files from .zip format.
Compresses files into .zip format.
Built-in bash commands
Some commands don’t even seem to exist if you try to look up their help
information in the man pages, and the commands themselves don’t show up
as files on your system. Remember, as you type commands at the prompt,
you’re communicating with a type of program called a shell. (The bash is
the default Linux shell.) The shell has a set of commands that you can use to
communicate with it, as shown in Table A-3.
Table A-3
Command
alias
env
export
history
unalias
Purpose
Shell Commands
Creates or lists command shortcuts.
Lists your current environment variables and their settings.
Whenever you’re told to set an environment variable, create
the variable and then use this command so that the variable
will be remembered properly.
Lists the last 1,000 commands you’ve typed.
Removes command shortcuts.
If you try to view the man page entries for some of these commands, you find
instead that the help information for BASH BUILTINS appears. To search
through this manual, press the forward slash (/) key to open the man search
interface — and then type the name of the command you want to search for.