SUM(1)SUM(1)

NAME

sum, md5sum, sha1sum – sum and count blocks in a file

SYNOPSIS

sum [ -5r ] [ file ... ]

md5sum [ file ... ]

sha1sum [ -2 bits ] [ file ... ]

DESCRIPTION

By default, sum calculates and prints a 32-bit hexadecimal checksum, a byte count, and the name of each file. The checksum is also a function of the input length. If no files are given, the standard input is summed. Other summing algorithms are available. The options are

-r

Sum with the algorithm of System V’s sum -r and print the length (in 1K blocks) of the input.  

-5

Sum with System V’s default algorithm and print the length (in 512-byte blocks) of the input.  

Sum is typically used to look for bad spots, to validate a file communicated over some transmission line or as a quick way to determine if two files on different machines might be the same.

Md5sum computes the 32 hex digit RSA Data Security, Inc. MD5 Message-Digest Algorithm described in RFC1321.

Sha1sum computes the 40 hex digit National Institute of Standards and Technology (NIST) SHA1 secure hash algorithm described in FIPS PUB 180-1, by default. Given the 2 option, it instead computes the bits-bit NIST SHA2 secure hash algorithm described in FIPS PUB 180-2 and prints the hash in hex. Currently supported values of bits are 224, 256, 384, and 512.

SOURCE

/sys/src/cmd/sum.c
/sys/src/cmd/md5sum.c
/sys/src/cmd/sha1sum.c

SEE ALSO

cmp(1), wc(1), sechash(2)