what does all this statments means? Post: 302156877

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Top Forums Shell Programming and Scripting what does all this statments means? Post 302156877 by Perderabo on Wednesday 9th of January 2008 10:43:43 AM

01-09-2008

Administrator Emeritus

sqlplus is a program that wants to read sql commands. You could put sql commands into a file and have sqlplus read that file via:
sqlplus < do_this.txt
but now you have a bunch a extra files to go with your shell script. By using a "here document" you can include a text data file directly in the script.

An example from the command line:

Code:

$
$ cat math.txt
1 + 1
$ bc < math.txt
2
$
$
$
$ bc <<anything
> 1 + 1
> anything
2
$

That "anything" is just some way to let the shell know when the input is finished. The "here document" extends to a line with just "anything" on it. This means that I cannot have a line in my "here doc" of just "anything". So I must pick a delimiting string that will not collide with my data.

Perderabo

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LEARN ABOUT REDHAT

beav

BEAV(1) 						      General Commands Manual							   BEAV(1)

NAME

       beav - binary file editor and viewer

SYNOPSIS

       beav [file...]

DESCRIPTION

       This  is  a  brief  description	of  the minimal set of commands that are necessary to start using beav effectively.  For more information,
       review the file /usr/share/doc/beav/beav140.txt.gz.

       The file-visit command, Ctl-X Ctl-V, can be used to read a file in for editing.	 The file can also be read in from the command line;  beav
       <edit_file>.

       Data is displayed in one or more windows.  These commands can be used to navigate around the windows.

	      move-back-char	  Ctl-B     moves left
	      move-back-line	  Ctl-P     moves up
	      move-forw-char	  Ctl-F     moves right
	      move-forw-line	  Ctl-N     moves down
	      window-delete	  Ctl-X 0   delete window
	      window-expand	  Ctl-X 1   expand window

       The move-to-byte command, Ctl-X G, will prompt you for a byte position to move to.

       These commands will insert a zero byte at the cursor position or delete the byte at that position.

	      insert-unit	  Ctl-X I
	      delete-forw-unit	  Esc D

       The file-save command, Ctl-X Ctl-S, will save the data to the file if a change has been made.

       The help command, Esc ?, will display a list of all commands and their current key bindings.

       The abort-cmd command, Ctl-G, will abort any command that is in operation.

       The quit-no-save command, Ctl-X Ctl-C, will exit beav.  If there is any data that has not been saved you will be warned.

FILES

       /usr/share/doc/beav/beav140.txt.gz

																	   BEAV(1)