Linux Commands #1

May 28, 2006

www.oracle .com articles

According to the linux Howto, below is the basic format for linux commands.

command [option] [source file(s)] [target file]

To get some inline help while on console mode. try any of the ff:

1. man “command”

> man echo 
ECHO(1)           User Commands                  ECHO(1)

NAME
       echo - display a line of text

SYNOPSIS
       echo [OPTION]... [STRING]...

DESCRIPTION
       NOTE:  your shell may have its own version 
       of echo which will supercede the version 
       described here. Please refer to your shells
       documentation for details about the options 
       it supports.

       Echo the STRING(s) to standard output.

       -n     do not output the trailing newline

       -e     enable interpretation of the backslash-
              escaped characters listed below

       -E     disable interpretation of those sequences 
              in STRINGs

       --help display this help and exit
...

2. whatis “command”

>whatis echo

echo                 (1)  - display a line of text
echo                 (1p) - write arguments to 
                             standard output
echo [builtins]      (1)  - bash built-in commands, 
                             see bash(1)
echo [curs_inopts]   (3x) - curses input options

3. help “command”

>help echo

echo: echo [-neE] [arg ...]
    Output the ARGs.  If -n is specified, the 
    trailing newline is suppressed.  If the -e 
    option is given, interpretation of the following 
    backslash-escaped characters is turned on:
        a      alert (bell)
        b      backspace
        c      suppress trailing newline
        E      escape character
        f      form feed
        n      new line
        r      carriage return
        t      horizontal tab
        v      vertical tab
              backslash
        num    the character whose ASCII code is 
                NUM (octal).

    You can explicitly turn off the interpretation 
    of the above characters with the -E option.

Each command displays different degrees of information regarding the command providing flexibility in mastering the console shell. In the next posts of this series, a “help” sheet of the command of the day will be provided. I’ll also try to provide usage samples.