Next week I am getting an exam on using basic commands and shell scripting using terminal in Ubuntu. Please help me out with two quick questions:
-Does a practice environment for the Ubuntu terminal exist? I don't want to dual boot with Linux, so I want to find somewhere I could practice using some basic terminal commands as Cygwin seems to be quite different from the ubuntu terminal.
-What does the col command in Linux do? The manual page is here: Link, but I find that hard to understand, and since it doesn't work in Cygwin, it's hard to interpret! Also, why would one use man piped to col -b -x?
Thank you very much and sorry for the probably silly questions!
You can use the Ubuntu LiveCD boot (boots up an Ubuntu system without actually installing it) and experiment with the Ubuntu terminal shell. Its actually the same CD as the standard Ubuntu installtion CD... you just chose "Try Ubuntu" instead of "Install Ubuntu" once it boots up: https://help.ubuntu.com/community/LiveCD
col is program to filter out reverse-linefeeds (i.e. the backspace character) from text input. In the olden days of line printers, a common method to achieve boldface print was to print a character, then print a backspace character, then print the character again. This would make the printer strike the character twice in the same place. Some programs would emit text files formatted in this way (man is one such program)-- but if you then tried to display that text file to your terminal screen, you might end up seeing something like this: "here is b^Hbo^Hol^Hld^Hd text".
col -b simply filters text input to strip out those extra backspace and double-strike characters. The -x option converts tab characters to space characters, which might be useful if the output was formatted for a device with a particular tab width, but then displayed on a different device.
man pages often have the backspace/double-strike text embedded in them, so man piped into col was often useful.
Nowadays, most terminal emulators actually know how to handle the backspace/double-strike, so col doesn't get used as much.