sum(1)

NAME

sum — print checksum and block or byte count of file(s)

SYNOPSIS

sum [-r] [-p] [file ...]

Remarks

sum is obsolescent and should not be used in new applications that are intended to be portable between systems. Use cksum instead (see cksum(1)).

DESCRIPTION

sum calculates and prints to standard output a checksum for each named file, and also prints the size of the file in 512 byte blocks, rounded up.

The default algorithm is a 16-bit sum of the bytes in which overflow is ignored. Alternate algorithms can be selected with the -r and -p options.

Standard input is used if no file names are given.

sum is typically used to verify data integrity when copying files between systems.

Options

sum recognizes the following options:

-r: Use an alternate algorithm in which the 16-bit sum is right rotated with each byte in computing the checksum.
-p: Use the 32-bit cyclical redundancy check (CRC) algorithm used by cksum.

RETURN VALUE

sum returns the following values upon completion:

0: All files were processed successfully.
>0: One or more files could not be read or some other error occurred.

If an inaccessible file is encountered, sum continues processing any remaining files, but the final exit status is affected.

DIAGNOSTICS

Read error conditions are indistinguishable from end of file on most devices; check the block or byte count.

WARNINGS

This command is likely to be withdrawn from X/Open standards. Applications using this command might not be portable to other vendors' platforms. The usage of cksum(1) is recommended.

STANDARDS CONFORMANCE

sum: SVID2, SVID3, XPG2, XPG3