NAME

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

SYNOPSIS

­sum [ ­-5r ] [ ­file ...  ]

­md5sum [ ­file ...  ]

­sha1sum [ ­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.  If no ­files are given, the standard input is summed. 

­Sha1sum computes the 40 hex digit National Institute of Standards and Technology SHA1 secure hash algorithm described in FIPS PUB 180-1.  If no ­files are given, the standard input is summed. 

SOURCE

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

SEE ALSO

cmp(1), wc(1)

Plan 9  —  March 16, 2001