jacksum is a better utility for file integrity cheking

If you want to verify file download integrity you must install jacksum. 
Jacksum supports 58 popular standard algorithms (Adler32, BSD sum, Bzip2's CRC-32, POSIX cksum, CRC-8, CRC-16, CRC-24, CRC-32 (FCS-32), CRC-64, ELF-32, eMule/eDonkey, FCS-16, GOST R 34.11-94, HAS-160, HAVAL (3/4/5 passes, 128/160/192/224/256 bits), MD2, MD4, MD5, MPEG-2's CRC-32, RIPEMD-128, RIPEMD-160, RIPEMD-256, RIPEMD-320, SHA-0, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, Tiger-128, Tiger-160, Tiger, Tiger2, Tiger Tree Hash, Tiger2 Tree Hash, Unix System V sum, sum8, sum16, sum24, sum32, Whirlpool-0, Whirlpool-1, Whirlpool and xor8). 

How to use:

1.sudo aptitude install jacksum

2.jacksum -a md5 Nessus-4.2.2-ubuntu910_i386.deb -this command lists the md5 checksum hash

3. Or for sha1 like this jacksum -a sha1 Nessus-4.2.2-ubuntu910_i386.deb