MD5 and SHA1 Checksum Using Linux

A file checksum is useful when you want to verify the content of a file are same as the content you copied or downloaded somewhere. Basically it calculate and summarise every bits of the file into a small integer value. To verify content of the file are same as the source, simply do a checksum of the source and destination file, and compare the checksum value.

To calculate a MD5 checksum of any file, enter the following command at the Linux prompt:
md5sum <file_to_check>

To calculate a SHA-1 checksum of any file, enter the following command at the Linux prompt:
sha1sum <file_to_check>