Some of the useful Ubuntu commands along with its descriptions. This might be used as a handy reference to quickly know about the syntax of a command.
|wget URL||Downloads the file specified by the URL.|
|pwd||Displays the current directory you are in.|
|sudo||Allows the user to act like a superuser|
|sudo -i||Allows the user to get root access.|
|sudo apt-get install package_name||Allows the user to act like a superuser and install packages|
|cd directory_name||Changes from current directory to the mentioned directory.|
|cd ..||Moves back one directory|
|ls||To view the contents in a directory including files and sub-directories.|
|ls -a||To view the contents in a directory including hidden files.|
|man command||Displays the information about the command specified.|
|whereis file/directory||Shows where the specified file/directory is.|
|mkdir directory_name||Creates a directory with the given name.|
|mv oldname newname||Renames the file.|
|rm filename||Removes the specified filename.|
|rmdir directoryname||Removes the specified empty directory.|
|rm -r directoryname||Removes files and sub-directories in the specified directory.|
|ifconfig & iwconfig||Allows the user to look at the network configuration.|
|ping URL||Allows the user to test connectivity issues.|
|vi filename||Opens the specified file in the vi editor to view/make changes.|
|telnet ip_address||Connects to the specified IP address.|
|chmod 777 file_name||Modifies the permissions of the specified file.
The three digits in 777 represents users, groups and others.
|chmod -R 777 directory||Modifies the permissions of the specified directory recursively. Meaning it applies the changes for all the files and sub-directories.|