File Editors

There are three file editors available on the system; gedit, vi (unix editor- pronounced "vee-eye"), and Config File Manager. The jot and vi editors can be used to edit any file, whereas the Config File Manager can only be used to change the contents of the MR Configuration files.

1 Gedit Editor

Gedit is a very easy-to-use text editor for viewing or editing on the system. The geditjot editor can be started two different ways:

From a C-Shell, or
From the Service Desktop Utilities menu

2 Starting Gedit from the Utilities Menu

On the Service Desktop, select Utilities, File Editor (gedit), then Start….
An empty “gedit” tty window opens. To open a file to read or edit, use the File pulldown menu to select Open. In the pop-up window, select the file or use the File Browser to locate and open the desired file. Click OK.
When you're done viewing or editing the file, select the File pulldown menu to select Save, or Exit (without saving changes) as appropriate.

3 Starting Gedit from a C-Shell

On the Service Desktop, select C Shell….
In the C-shell window, type the directory path of the file you want to view or edit; for example: cd /test Enter.
To view or edit a file, type gedit filenameEnter.
When done viewing or editing the file, select File on the pulldown menu, then select Save, or Exit (without saving changes) as appropriate.

4 Vi Editor

The vi editor provides a tty window to edit or read files on the system. Invoking vi from within a C-Shell Tool displays up to 38 lines of a file. The vi editor has over 100 commands. It is difficult to use and is recommended only for experienced users. Table 1 provides an overview of the commands needed to navigate within a file and handle the major editing tasks.

Table 1. Basic vi Editor Commands
Command Types	Command	Description
Invoking vi	vi filename	Opens a window and displays about 30 lines of the file
Input Mode commands	l	Inserts text immediately in front of the cursor location
	a	Appends text immediately following the cursor location
	o	Appends text below the current line
	O	Inserts text above the current line
Exit/Input Mode	Esc	Places vi in command mode
Cursor positioning	h	Moves cursor one character to the left
	i	Moves cursor one character to the right
	j	Moves cursor down one line
	k	Moves cursor up one line
	H	Moves cursor to top of screen
	M	Moves cursor to the middle of the screen
	L	Moves cursor to the bottom of the screen
Saving and exiting vi	:w	Saves the changes to the current file
	:wq	Saves the changes to the current file and quits vi
	:q!	Quits vi without saving changes
Modifying text	x	Deletes the current character
	dd	Deletes the current line
	#dd	Deletes the current line and # lines following it
	r	Replaces the current character with the character typed next
	u	Undoes the most recent delete or change
	U	Undoes all changes on the current line
Search for Text String	/text string	Searches for the specified text throughout the file

The vi editor has two modes of operation: Input mode and Command mode. While in Input mode, whatever is typed at the keyboard is entered into the file at the location of the cursor. While in Command mode, you can position the cursor anywhere in the file, delete characters, lines or groups of lines, write the changes to the file, and quit the editor. To change from Input Mode to Command Mode, press Esc. The following is a listing of basic commands to begin using vi; refer to Table 1 for their full descriptions. A sample vi edit session is shown in Figure 1. Table 2 is a VI quick reference.

note:

All vi commands are case-sensitive.

Table 2. Vi Commands Quick Reference
Start vi editor	vi filename
Enter Input mode	i, a o, O
Exit Input mode	Esc
Cursor position commands	h, j, k, l, and Enter
Save and quit the editor	:w, :q!, :wq
Delete or replace text	x, dd, r u

5 Configuration File Manager

The Config File Manager is used to change the contents of the MR System configuration, Gradient configuration, SAR configuration, and Coil Configuration files via a GUI (Graphical User Interface) tool. Editing of configuration files using is covered in the Configuration File Manager procedure.