Erased Mail program, how can I get it back?

Question

Don't ask me why I erased the program, totally crazy, but now I would like it back and don't know how?
Can you please help me?

Answer 1

How to Use Pacifist to Replace Deleted OS X Applications
Download the shareware utility Pacifist from VersionTracker or MacUpdate. Use it to extract a fresh copy of the missing item(s) from the file archives on your OS X installation DVD. The file archives are in the /System/Installations/ folder (use Go to Folder option in the Go menu of the Finder.)
Here are Four Basic ways to use Pacifist (courtesy of George Orville.)
A. Drag a .pkg icon onto the Pacifist window .....proceed to step 7.
B. Click on “Open Package ....” and navigate to package desired and click “Open” in the open/save window.....proceed to step 7.
C. Insert Mac OS X installer CD and when it mounts, navigate to .... Menu->Go->Go to Folder.
In the path field enter or paste ....
/Volumes/disc name/System/Installation/Packages (where disc name is the name of the CD/DVD that you inserted.
• Click on the "Go" button .....
• Drag a .pkg to Pacifist..... proceed to step 7.
The package you'll need will have to be discovered by trial and error, but for most applications you should start with the Essentials.pkg and/or Additional Essentials.pkg.
D. Insert your Mac OS X install disk 1 .... and open Pacifist.
1. In Pacifist, select "Open Mac OS X Install Packages" ... dialog may appear asking for disk 2, then disk 3 and finally disk 1 again.... {if DVD is not used)...If “Stop Loading” is selected...the procedure will stop!!!
2a. When loading is complete, a new window appears, click the triangle to display contents of each package...Select item and proceed to step 7.
2b. or click the “Find” icon in the Pacifist window and type the name of the software you need.
3. In the list that comes back, click the top most entry for the item that you want. ..... that is the one for the English language.
4. On the top of the Pacifist window, click “verify” .... you will probably be prompted for your password.
5. Enter checks for.... “verify permissions” and “verify file contents.” and click “verify” ....enter password when prompted.... you will get back output which may look like this:
20 files were scanned.
20 of 20 files were present on the hard disk.
0 of 20 files had file permissions that did not match those specified in the package.
0 of 20 files had checksums that did not match those specified in the package.
6. Click “close”. Go to step 7.
Extract or Install........
7. In the Toolbar (upper left), you now have the option to extract or install. Click a file in the lower list and those two icons will be enabled.
8. If “Extract to...” is selected.... navigate to the location where the file will be placed, select “choose”, select “extract” in new dialog that appears,authenicate , if prompted, click “OK”.
9. In the next dialog, click “Extract”.
10. If “Install” is selected... dialog will appear with the location/path of the installed software. Click “Install”
11. Type in your password, click “OK”
• Pacifist will begin to extract files.
12. In steps 8/10ß.... you also have the choice to “cancel”
Notes.....
• Pacifist may find that a file it is installing already exists on the hard disk. Pacifist will present you with an alert panel....
Stop
Leave original alone
Update ..... Default selection
Replace .... Replace option should only be used on full install packages