Development Environment

Saving M-Files

After making changes to an M-file, you see an asterisk (*) next to the filename in the title bar of the Editor/Debugger. This indicates there are unsaved changes to the file.

To save the changes, use one of the Save commands in the File menu:

• Save--Saves the file using its existing name. If the file is newly created, the Save file as dialog box opens, where you assign a name to the file and save it. Another way to save is by using the save button on the toolbar. If the file has not been changed, Save is grayed out, but you can instead use Save As to save to a different filename.
• Save As--The Save file as dialog box opens, where you assign a name to the file and save it. You do not need to type the .m extension because MATLAB automatically assigns the .m extension to the filename. If you do not want an extension, type a . (period) after the filename.
• Save All--Saves all named files to their existing filenames. For all newly created files, the Save file as dialog box opens, where you assign a name to each file and save it.

You cannot save a file while in debug mode. First, exit debug mode and then save the file.

Note    Save any M-files you create and any MathWorks-supplied M-files that you edit in a directory that is not in the $matlabroot/toolbox directory tree. If you keep your files in $matlabroot/toolbox directories, they can be overwritten when you install a new version of MATLAB. Also note that locations of files in the $matlabroot/toolbox directory tree are loaded and cached in memory at the beginning of each MATLAB session to improve performance. If you save files to $matlabroot/toolbox directories using an external editor or add or remove in from these directories using file system operations, run rehash toolbox before you use the files in the current session. If you make changes to existing files in $matlabroot/toolbox directories using an external editor, run clear functionname before you use the files in the current session. For more information, see rehash or Toolbox Path Caching.

Autosave

As you make changes to a file in the Editor, every five minutes the Editor automatically saves a copy of the file to a file of the same name but with an .asv extension. The autosaved copy is useful if you have system problems and lose changes made to your file. In that event, you can open the autosaved version, filename.asv, and then save it as filename.m to use the last good version of filename.

Use Autosave Preferences for the Editor/Debugger to turn the autosave feature off or on, to specify the number of minutes between automatic saves, and to specify the file extension and location for autosaved files.

Autosaved files are not automatically deleted when you delete the source file. So if, for example, you rename a file, delete the .asv version of the original filename.

If the M-file you are editing is in a read-only directory, an autosave copy of the file is not made.

Running M-Files from the Editor/Debugger

You can run a script or a function that does not require an input argument directly from the Editor/Debugger. Click the run button on the toolbar, or select Run from the Debug menu.

If the file is not in a directory on the search path or in the current directory, a dialog box appears, presenting you with options that allow you to run the file. You can either change the current directory to the directory containing the file, or you can add the directory containing the file to the search path.

Note that if the file has unsaved changes, running it from the Editor/Debugger automatically saves the changes before running. In that event, the menu item is Save and Run.

See Running an M-File with Breakpoints for additional information about running M-files while debugging.

Incremental Search

Printing an M-File