Some Basic Linux And Unix Commands

cat
Lets you view the contents of a file. Many linux commands can use the redirection symbol > to redirect the output of the command. For example, use the redirection symbol with the cat command to copy a file: cat /etc/shells > newfile ( the contents of the shells file are written to newfile ).
cd
Changes the directory.
chmod
This command changes the attributes assigned to a file and is similar to the DOS Attrib command.
clear
Clears the screen. This command is useful when the screen has become cluttered with commands and data that you no longer need to view.
cp
Used to copy a file.
date
Entered alone, this command displays the current system date settings. Entered in the format date , this command sete the system date.
echo
Displays information on the screen.
fdisk
Creates or makes changes to a hard drive partition table.
grep
Searches for a specific pattern in a file or in multiple files.
hostname
Displays a server’s FQDN.
ifconfig
Used to troubleshoot problems with network connections under TCP/IP, this command can disable and enable network cards and release and renew the IP address assigned to these cards.
kill
Kills a process instead of waiting for the process to terminate.
Ls
This command is similar to the DOS Dir command, which displays a list of directories and files.
man
Displays the online help manual, called man pages.
mkdir
This command makes a new directory.
|more
Appended to a command to display the results of the command on the screen one page at a time.
mv
Moves a file or renames it, if the source and destination are the same directory.
nestat
Shows statistics and status information for network connections and routing tables.
nslookup
Queries doman name servers to look up domain names.
ping
Used to test network connections by sending a request packet to a host. If a connection is successful, the host will return a response packet.
ps
Displays the process table so that you can identify process ID’s for currently running processes.
pwd
Shows the name of the present working directory.
reboot
Reboots the system.
rm
Removes the file or files that are specified.
rmdir
Removes a directory.
route
Entered alone, this command shows the current configuration of the IP routing table. Entered in the following format, it configures the IP routing table: route
vi
Launches a full screen editor that can be used to edit a file.
whatis
Displays a brief overview of a command.