How to check crc of a file?

As always(maybe sometimes), google is my friend:

$ sudo apt-get install libarchive-zip-perl
$ crc32 my_file

One way to calculate it is this:

cksum "file"

Another one is

crc32 "file"

To use this last command you need to install libarchive-zip-perl package

I'd use the internal md5sum one of the provided sha programs:

sha1sum (1)          - compute and check SHA1 message digest
sha224sum (1)        - compute and check SHA224 message digest
sha256sum (1)        - compute and check SHA256 message digest
sha384sum (1)        - compute and check SHA384 message digest
sha512sum (1)        - compute and check SHA512 message digest

cksum is pretty much outmoded these days because of its problems.