Even more useful Linux command-line tips and information
How large in total are the contents of a folder? This command will print that for you. This is the total disk usage of all files in the current folder.
ubuntu ~ $ sudo du -ackh /usr | tail -n 1 2.7G total
To copy and paste text from an xterm window if you are using a tiling window manager like Awesome as I am at the moment and you can not use Ctrl-C & Ctrl-V, then simply highlight the desired text in the xterm and press both mouse buttons at once, this will copy the text to a buffer. Then you may paste the text in the desired place with the middle mouse button. If you highlight a command with the mouse and press the middle mouse button, then the text will be copied and pasted in one operation, this may not always be what you want. I have used this to copy from an xterm window to the Firefox web browser and it worked a treat. This is the traditional way of copying and pasting text in X.
To close an xterm you have no need of, you may type exit in the terminal prompt, or you can press Ctrl-D and this will also close the terminal window.
This command will print the disk space remaining on the root / folder.
ubuntu ~ $ df -Hla / | head -n 2 Filesystem Size Used Avail Use% Mounted on /dev/xvda1 32G 28G 3.0G 91% /
And this command will print all processes that your user is running.
ubuntu ~ $ ps aux | grep $LOGNAME root 17673 0.0 0.1 107748 1136 ? Ss 21:59 0:00 sshd: ubuntu [priv] ubuntu 17776 0.0 0.1 107896 1224 ? S 21:59 0:00 sshd: ubuntu@pts/0 ubuntu 17779 0.0 0.0 4452 152 pts/0 Ss 21:59 0:00 -sh ubuntu 17783 0.0 0.3 22080 3456 pts/0 S 21:59 0:00 bash ubuntu 17816 0.0 0.1 17172 1276 pts/0 R+ 22:03 0:00 ps aux ubuntu 17817 0.0 0.0 10472 904 pts/0 S+ 22:03 0:00 grep --color=auto ubuntu