| LINUX COMMAND | OPTIONS | COMMENTS |
| ls | -ahl | List, the equivalent of the dir command. Displays the contents of the current directory. The options -ahl mean a=all files & directories, h=human readable file sizes (MB & kB), l=long listing with all permissions/attributes. |
| cd /path | Change to stated directory. | |
| cd ~ | Change to "home" directory. | |
| cd / | Change to "root" directory. | |
| cp /path/file /path/file | -R | Copy file from directory... to .... directory. |
| rm /path/file | -r | Remove or delete file. -r = recursive. |
| mv /path/file /path/file | Move file from one directory to another. | |
| mkdir name | Create a directory called "name" in current directory. | |
| mkdir /path/name | Create a directory called "name" at the path stated. | |
| rmdir name | Remove or delete the directory called name in current directory. | |
| passwd | Change password of current logged in user. | |
| su | To update current login to "super user" i.e. root! Enter root password at the prompt. | |
| du /path | -csh | Show the amount of disk used by the stated directory. -c= show grand total, -s= summarise, -h= human readable. |
| df | -h | Display free space on all mounted devices (HDDs). -h=human readable sizes, MB & kB. |
| chmod 644 file | -R | Modify the file permissions on file to 644 i.e. owner: read & write, group: read, others: read. (see permissions) |
| chown owner:group file | -R | Change the owner (& group if required) of the file to the stated owner & group. Can also be used with -R. |
| chgrp new_group file | -R | Change the group to which the file belongs to new_group. With the -R option you can change recursively all files within a given directory. |
| tar /path/file | -xvf | Unpack the tar file. |
| gzip /path/* file | -r | Zip all the files found within the /path directory into "file". |
| gunzip /path/file | Unpack the zip file. | |
| find / -name fetchmail | Find is a search programme. i.e. search through the "root directory" / for the file with the name fetchmail, & display it's location. | |
| ln /path/file file | Link to the file with the target at /path/file into our current directory & call the link file. | |
| man ls | Display the "manual page" for the programme ls. | |
| info ls | Display the "info pages" for the programme ls. This is similar to the man command. | |
| crontab | -e -l | Setting up the cron daemon to run programmes or scripts at predetermined times. -e= edit cron jobs, -l=list cron jobs. |
| mkfs.ext2 /dev/fd0 | "make file system extended 2" on the device floppy, i.e. format the floppy. | |
| less | (many!!) | Very useful command for piping, eg. ls -ahl /etc will give you a HUGE list of files, by piping this command through to the less command (ls -ahl /etc | less) you can view this list one "screen" at a time, starting from the first screen. |
| more | Same as the less command, except you start at the last screen. | |
| head /path/file | Displays by default the first 10 lines of the specified file. | |
| tail /path/file | Displays by default the last 10 lines of the specified file | |
| mount /dev/fd0 /path | Mount the device Floppy into the specified directory | |
| umount /dev/fd0 | Unmount the Floppy. | |
| ps | -a | List all running processes, including PID number (PID refers to the numerical number for a running process. -a =all |
| pstree | -p | Lists all running processes, including it's PID, in a hierachle form. -p= show PID number. |
| kill 1086 | Stop the programme with the process number 1086. | |
| netstat | -an | Used to check the network statistics. Displays (with the -an options) all the ports that are open & also any Ips that are connected to your server. |
| ping | Check whether a given host is "online". Enter either the hosts IP address or the domain name. | |
| traceroute www.highasakite.net | Used to trace the connection from your machine to the queried host, i.e. traceroute www.highasakite.net. Traceroute displays all the servers that are used to connect you to the host. | |
| nslookup 62.226.127.152 | Resolve the IP number into a domain name | |
| ifconfig | Display all your IP addresses, i.e. eth0, eth1, ... , ppp0 | |
| who | Displays a list of which user is logged on to your server | |
| fdisk | Like under DOS it's used here to partition HDDs. |