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Full Discussion: Tail -f | grep > output.txt
Top Forums UNIX for Dummies Questions & Answers Tail -f | grep > output.txt Post 302928700 by RudiC on Sunday 14th of December 2014 01:08:31 PM
Old 12-14-2014
That might be due to buffering. On linux, one of the coreutils is stdbuf that allows to modify the way programs use their input and output buffers. Try:
Code:
tail -f /var/log/syslog | stdbuf -o0 grep "Searchstring" > output.txt &

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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
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