Why Unix is Beautiful

Unix with the Bash shell is beautiful because you can string a list of simple commands together to instruct computers to do complex things.  Folks sometimes refer to this as “sedgrepawk”.  Those are Unix commands with cryptic names – they sound like mysterious incantations of wizardry.  And in effect they are.

Here are some examples:

1. What users are on this box?

The /etc/passwd file contains a list of all users the box.  To see the last 5 people added to system you can type:

$ cat /etc/passwd | tail – 5

The dollar sign is the prompt (you don’t type that)

the cat command lists out the contents of a file.

Piping that (|) into tail -5 lists the last 5 rows.

The results may look like this:

dlink:x:2000:2000:David Link:/home/dlink:/bin/bash
mysql:x:104:111:MySQL Server,,,:/nonexistent:/bin/false
jzlink:x:2001:2000:Julia Link:/home/jzlink:/bin/bash
ftp:x:105:112:ftp daemon,,,:/srv/ftp:/bin/false

This shows  name, x, user id, group id, description, home directory and default shell for each user.  x is a place holder for the password.

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