Your Internet Consultant - The FAQs of Life Online

3.31. What other important UNIX commands should I know about?

• man. OK, I already mentioned this one, but I'm mentioning it again to make sure that you know how to RTFM (read the manual). The man command shows you the manual page for a particular command. For instance, man grep will give you lots of information about the grep command.

$ man grep
Reformatting page.  Wait... done
GREP(1V)                 USER COMMANDS                   GREP(1V)

NAME
     grep, egrep, fgrep - search a file for a string  or  regular
     expression

SYNOPSIS
     grep [ -bchilnsvw ] [ -e expression ] [ filename... ]

DESCRIPTION
     Commands of the grep family search the input filenames  (the
     standard  input default) for lines matching a pattern.  Nor-
     mally, each line found is copied  to  the  standard  output.
     grep  patterns  are limited regular expressions in the style
     of ed(1).   egrep  patterns  are  full  regular  expressions
     including  alternation.   fgrep patterns are fixed strings -
     no regular expression metacharacters are supported.

OPTIONS
     -b   Precede each line by the block number on which  it  was
          found.  This is sometimes useful in locating disk block
          numbers by context.

• vi or emacs or others. Text editors, or programs that allow you to create text files (such as e-mail messages, programs or letters to Aunt Zelda). Ask your local guru what editor you should use. The vi editor is simple but not exceptionally easy to learn. In contrast, emacs is a software behemoth that will edit files, tell your fortune, and teach you to make cookies. (Really.)
• lpr or print. May let you print a text file on a printer connected to the UNIX computer. Two caveats: first, never try to print a nontext file. Anything that looks like gibberish when viewed onscreen with the cat command will look worse on paper. Second, if you're hacking from a college computer lab or your office and you know there's a printer down the hall, feel free to use the print command. If you're using a dial-up UNIX system hundreds of miles away, however, don't use the printer unless you intend to drive there to pick up your printout!
• grep. Stands for Global Regular Expression Print, which is a verbose way of saying that this program will search through files and output any lines that contain text that you specify. If you've ever read Usenet news, your home directory contains a hidden file called .newsrc, which lists all the newsgroups available to you. Typing grep amiga .newsrc will list all the lines in the file that contain the word amiga.
• passwd. Allows you to change your password. Typing passwd will prompt you for your old password, then ask you to type your new password twice. Passwords you type should never be visible on your screen.

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