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UNIX for Beginners Questions & Answers
Understanding a script for sum
Post 303015605 by uniran on Sunday 8th of April 2018 09:41:05 AM
04-08-2018
Quote:
That obviously is a (bourne) shell function. As you don't mention your shell's version, bash assumed.
man bash
uring expansion, the "multiword character" of $1 is lost, and the shell makes up this five item list: 8 8 8 9 9 across which the for loop iterates, resulting in 42 plus x's initial value. Be aware that the x=$1 assignment has nothing to do with the $1 that func() is called with; function get their own set of parameters when called.
And, remove the space in the let assignment.
man bash
uring expansion, the "multiword character" of $1 is lost, and the shell makes up this five item list: 8 8 8 9 9 across which the for loop iterates, resulting in 42 plus x's initial value. Be aware that the x=$1 assignment has nothing to do with the $1 that func() is called with; function get their own set of parameters when called.And, remove the space in the let assignment.
B.In truth, the for loop doesn't iterates just three times for $1 $2 $3 as defined but rather one time for each existed item,total of five iterations in this case ?
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LEARN ABOUT HPUX
sum
sum(1) General Commands Manual sum(1) NAME
sum - print checksum and block or byte count of file(s) SYNOPSIS
[file ...] Remarks is obsolescent and should not be used in new applications that are intended to be portable between systems. Use instead (see cksum(1)). DESCRIPTION
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 and options. Standard input is used if no file names are given. is typically used to verify data integrity when copying files between systems. Options recognizes the following options: Use an alternate algorithm in which the 16-bit sum is right rotated with each byte in computing the checksum. Use the 32-bit cyclical redundancy check (CRC) algorithm used by RETURN VALUE
returns the following values upon completion: All files were processed successfully. One or more files could not be read or some other error occurred. If an inaccessible file is encountered, 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. SEE ALSO
cksum(1), wc(1). STANDARDS CONFORMANCE
sum(1)