ref: d5fc608059dee5f65ddfdf3e230bb8d458ccf43f
dir: /sys/man/1/sum/
.TH SUM 1 .SH NAME sum, md5sum, sha1sum \- sum and count blocks in a file .SH SYNOPSIS .B sum [ .B -5r ] [ .I file ... ] .PP .B md5sum [ .I file ... ] .PP .B sha1sum [ .B -2 .I bits ] [ .I file ... ] .SH DESCRIPTION By default, .I sum calculates and prints a 32-bit hexadecimal checksum, a byte count, and the name of each .IR file . The checksum is also a function of the input length. If no .IR file s are given, the standard input is summed. Other summing algorithms are available. The options are .TF -r .PD .TP .B -r Sum with the algorithm of System V's .B "sum -r" and print the length (in 1K blocks) of the input. .TP .B -5 Sum with System V's default algorithm and print the length (in 512-byte blocks) of the input. .PP .I 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. .PP .I Md5sum computes the 32 hex digit RSA Data Security, Inc. MD5 Message-Digest Algorithm described in RFC1321. .PP .I 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 .L 2 option, it instead computes the .IR bits -bit NIST SHA2 secure hash algorithm described in FIPS PUB 180-2 and prints the hash in hex. Currently supported values of .I bits are 224, 256, 384, and 512. .SH SOURCE .B /sys/src/cmd/sum.c .br .B /sys/src/cmd/md5sum.c .br .B /sys/src/cmd/sha1sum.c .SH "SEE ALSO" .IR cmp (1), .IR wc (1), .IR sechash (2)