Many of Ubuntu’s shell commands manipulate text strings, so if you want to be able to feed them the contents of files, you need to be able to output those files as text. Enter the
cat command, which prints the contents of any files you pass to it.
Its most basic use is like this:
matthew@seymour:~$ cat myfile.txt
That prints the contents of
myfile.txt. For this usage there are two extra parameters that are often used:
-n numbers the lines in the output, and
-s (“squeeze”) prints a maximum of one blank line at a time. That is, if your file has 1 line of text, 10 blank lines, 1 line of text, 10 blank lines, and so on,
-s shows the first line of text, a single blank line, the next line of text, a single blank ...