Linux in a Nutshell, Fourth Edition

Beginner’s Guide

If you’re just beginning to work on a Linux system, the abundance of commands might prove daunting. To help orient you, the following lists present a sampling of commands on various topics.

Communication

ftp	File Transfer Protocol.
login	Sign on.
rlogin	Sign on to remote system.
rsh	Run shell or single command on remote system (not particularly secure).
ssh	Run shell or single command on remote system (secure).
talk	Exchange messages interactively with other terminals.
telnet	Connect to another system.
tftp	Trivial File Transfer Protocol.
uudecode	Decode file prepared for mailing by uuencode.
uuencode	Encode file containing binary characters for mailing.
vacation	Respond to mail automatically.

Comparisons

cmp	Compare two files, byte by byte.
comm	Compare items in two sorted files.
diff	Compare two files, line by line.
diff3	Compare three files.

File Management

cat	Concatenate files or display them.
chfn	Change user information for finger, email, etc.
cksum	Compute checksum.
chmod	Change access modes on files.
chsh	Change login shell.
cp	Copy files.
csplit	Split a file into pieces with a specific size or at specific locations.
dd	Copy files in raw disk form.
file	Determine a file’s type.
head	Show the first few lines of a file.
less	Display files by screenful.
ln	Create filename aliases.
ls	List files or directories.
merge	Merge changes from different ...