Changed made in a buffer do not affect the file on disk until the buffer is saved.
File>Save (shortcut: Control-S) saves the current buffer to disk.
File>Save As saves the buffer to a different specified file on disk. The buffer is then renamed, and subsequent saves also save to the specified file. Note that using this command to save over an already open buffer will close that buffer, to avoid having two buffers open with the same path name.
File>Save a Copy As saves the buffer to a different specified file on disk, but doesn't rename the buffer, and doesn't clear the "modified" flag. Note that using this command to save over an already open buffer will automatically reload that buffer.
File>Save All (shortcut: Control-E Control-S) saves all open buffers to disk, asking for confirmation first.
The autosave feature protects your work from computer crashes and such. Every 30 seconds, all buffers with unsaved changes are written out to their respective file names, enclosed in hash ("#") characters. For example, program.c will be autosaved to #program.c#.
Saving a buffer using one of the commands in the previous section automatically deletes the autosave file, so they will only ever be visible in the unlikely event of a jEdit (or operating system) crash.
If an autosave file is found while a buffer is being loaded, jEdit will offer to recover the autosaved data.
The autosave interval can be changed in the Loading and Saving pane of the Utilities>Global Options dialog box; see the section called "The Global Options Dialog Box".
The backup feature can be used to roll back to the previous version of a file after changes were made. When a buffer is saved for the first time after being opened, its original contents are "backed up" under a different file name.
The default behavior is to back up the original contents to the buffer's file name suffixed with a tilde ("~"). For example, paper.tex will be backed up to paper.tex~.
The backup feature can also be configured in the Loading and Saving pane of the Utilities>Global Options dialog box. It can be customized to do any of the following:
Save multiple, numbered backups, named filename~number~.
Add a prefix to the backed-up file name.
Adds a suffix to the backed-up file name (the default is "~").
Backups can optionally be saved in a specified backup directory, instead of the directory of the original file. This can reduce clutter.
Backups can also optionally be created every time a buffer is saved; the default is to only create a backup the first time a buffer is saved after being opened.