12-31-2012
Quote:
Originally Posted by
pandeesh
And also i want to understand the internal implementation of zcat.
i believe zcat should un-compress the original file intermediately somewhere and read.
although we don't see any impact in small files, i want to make sure the impact for the huge files.
Yes. It uses temp memory to perform un compression work.
So the impact might be how much load it will ask to do the things. I believe while performing zcat oparations on a big file, there is large chances that system will throw low memory space error.
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LEARN ABOUT NETBSD
zegrep
ZGREP(1) BSD General Commands Manual ZGREP(1)
NAME
zgrep, zegrep, zfgrep -- print lines matching a pattern in gzip-compressed files
SYNOPSIS
zgrep [grep-flags] [--] pattern [files ...]
zegrep [grep-flags] [--] pattern [file ...]
zfgrep [grep-flags] [--] pattern [file ...]
DESCRIPTION
zgrep runs grep(1) on files or stdin, if no files argument is given, after decompressing them with zcat(1).
The grep-flags and pattern arguments are passed on to grep(1). If an -e flag is found in the grep-flags, zgrep will not look for a pattern
argument.
zegrep calls egrep(1), while zfgrep calls fgrep(1).
EXIT STATUS
In case of missing arguments or missing pattern, 1 will be returned, otherwise 0.
SEE ALSO
egrep(1), fgrep(1), grep(1), gzip(1), zcat(1)
AUTHORS
Thomas Klausner <wiz@NetBSD.org>
BSD
December 28, 2003 BSD