How to quickly check a file's checksum in OS X

How to quickly check a file's checksum in OS X
To verify the checksum, first proceed with the download and wait for it to complete. Then open the Terminal application in OS X and type the command "shasum" followed by a single space. After you do this, locate the downloaded disk image file, and drag it to the Terminal window to complete the full path to the image file.Then press Enter to execute the command, and a SHA checksum will be computed for the file. Now compare this locally computed checksum to the one listed on the download Web site, and if they match, the file has been verified. If the file you have does not match the one on the Web site, it could be that the file on the site has been updated or otherwise changed and the developer forgot to update the checksum, or it could be from corruption in the file during the transfer, or from unsolicited tampering with the file. Either way, if the checksums do not match, contact the developer before opening it.Another common checksum routine is the md5 checksum, which can be checked similarly by running the command "md5" in the Terminal in a similar way as the "shasum" command mentioned above.Questions? Comments? Have a fix? Post them below or e-mail us!Be sure to check us out on Twitter and the CNET Mac forums.