Re: gnu grep -o flag
On Wed, Mar 24, 2010 at 11:13 PM, Philip Guenther guent...@gmail.com wrote:
On Wed, Mar 24, 2010 at 1:06 PM, Philip Guenther guent...@gmail.com
wrote:
...
Hmm, missing quote, and the expressions can be combined, but as a
portable solution this is indeed the right answer.
B B sed -n -e 's/.*\(PATTERN\).*/\1/p'
The 'portable' solution that doesn't have those problems is to use a
nuke^W^Wperl:
B B perl -nle 'while(m((PATTERN))g){print $1}'
ahem, is perl really everything these days?
and how portable that is?
is awk completely disregarded as a usable tool?
awk '{ s = $0; while (match(s,PATTERN)) { print substr(s, RSTART,
RLENGTH); s = substr(s, RSTART + RLENGTH); } }'
this gives me the same results are your perl string
(which is shorter of course, after all it's perl).
it also gives the same results are grep -o on
a debian system i have access to.
also awk uses, AFAIK, ERE, in which case
the greediness may be controlled.
Re: gnu grep -o flag
On Wed, Mar 24, 2010 at 09:10:48PM -0500, Ed Ahlsen-Girard wrote:
I'm sure there is a case in which sed should be used instead of perl,
but I haven't run across it yet.
I've encountered two cases over the past 20 years.
1) Perl is not installed and probably will never be installed.
That ceased to be the case about 10 years ago, and then started
being the case again as folks started replacing the firmware
on consumer grade routers.
2) The time to load perl from disk and the memory consumed doing
so would create a significant load on the system if run every minute.
But that was in the days of perl4.
But in the end I opted for the awk implementation. The implementation
was readable :-).
And that leads to my gripe...
What is a case of something where sed should be used instead of
awk or some iteration of var2=${var1##*/} and related constructs.
I do know that the use of var2=`echo $var1 | sed -e 's,^.*/,,`
has a high correlation with gems like
if [ -z $var ]; then ...
--
Chris Dukes
Re: gnu grep -o flag
On Mar 24 19:00:06, Gregory Edigarov wrote: Hello Everybody, Just wonder how could one implement what gnu grep -o flag does using our toolchain? from ggrep(1): -o, --only-matching Show only the part of a matching line that matches PATTERN. Hint: what does g/re/p stand for?
Re: gnu grep -o flag
On Wed, 24 Mar 2010 19:00:06 +0200 Gregory Edigarov wrote: Hello Everybody, Just wonder how could one implement what gnu grep -o flag does using our toolchain? from ggrep(1): -o, --only-matching Show only the part of a matching line that matches PATTERN. maybe try this: sed -n -e 's/.*\(PATTERN\).*/\1/ -e /PATTERN/p
Re: gnu grep -o flag
huh? didn't you just grep for that? On Wed, Mar 24, 2010 at 07:00:06PM +0200, Gregory Edigarov wrote: Hello Everybody, Just wonder how could one implement what gnu grep -o flag does using our toolchain? from ggrep(1): -o, --only-matching Show only the part of a matching line that matches PATTERN. -- With best regards, Gregory Edigarov
Re: gnu grep -o flag
No. i...@iso2:~/Desktop$ grep import IDS_targets.py import MySQLdb import socket import getpass import datetime i...@iso2:~/Desktop$ grep import -o IDS_targets.py import import import import On Wed, 24 Mar 2010 13:33 -0500, Marco Peereboom sl...@peereboom.us wrote: huh? didn't you just grep for that? On Wed, Mar 24, 2010 at 07:00:06PM +0200, Gregory Edigarov wrote: Hello Everybody, Just wonder how could one implement what gnu grep -o flag does using our toolchain? from ggrep(1): -o, --only-matching Show only the part of a matching line that matches PATTERN. -- With best regards, Gregory Edigarov
Re: gnu grep -o flag
On Wed, Mar 24, 2010 at 1:00 PM, Gregory Edigarov g...@bestnet.kharkov.ua wrote: Just wonder how could one implement what gnu grep -o flag does using our toolchain? With a 10 line patch.
Re: gnu grep -o flag
On Wed, Mar 24, 2010 at 10:17 AM, Christopher Zimmermann madro...@zakweb.de wrote: On Wed, 24 Mar 2010 19:00:06 +0200 Gregory Edigarov wrote: Just wonder how could one implement what gnu grep -o flag does using our toolchain? from ggrep(1): -o, --only-matching Show only the part of a matching line that matches PATTERN. maybe try this: sed -n -e 's/.*\(PATTERN\).*/\1/ -e /PATTERN/p Hmm, missing quote, and the expressions can be combined, but as a portable solution this is indeed the right answer. sed -n -e 's/.*\(PATTERN\).*/\1/p' If you need extended (egrep-style) regexps, then the most portable solution is a chunk of awk (left as an exercise for the student); the less-portable-but-works-in-4.7 solution is to use -E option to sed: sed -n -E 's/.*(PATTERN).*/\1/p' Philip Guenther
Re: gnu grep -o flag
On Wed, 24 Mar 2010 13:06:12 -0700 Philip Guenther wrote: On Wed, Mar 24, 2010 at 10:17 AM, Christopher Zimmermann madro...@zakweb.de wrote: On Wed, 24 Mar 2010 19:00:06 +0200 Gregory Edigarov wrote: Just wonder how could one implement what gnu grep -o flag does using our toolchain? from ggrep(1): -o, --only-matching Show only the part of a matching line that matches PATTERN. maybe try this: sed -n -e 's/.*\(PATTERN\).*/\1/ -e /PATTERN/p Hmm, missing quote, and the expressions can be combined, but as a portable solution this is indeed the right answer. sed -n -e 's/.*\(PATTERN\).*/\1/p' right. This one looks nicer. If you need extended (egrep-style) regexps, then the most portable solution is a chunk of awk (left as an exercise for the student); the less-portable-but-works-in-4.7 solution is to use -E option to sed: sed -n -E 's/.*(PATTERN).*/\1/p' sed -E !?! Great! Now I know why I upgraded to -current.
Re: gnu grep -o flag
On Wed, Mar 24, 2010 at 1:06 PM, Philip Guenther guent...@gmail.com wrote:
...
Hmm, missing quote, and the expressions can be combined, but as a
portable solution this is indeed the right answer.
sed -n -e 's/.*\(PATTERN\).*/\1/p'
Actually, there are two bug in that, an obvious one and a subtle one.
The obvious one is that it only prints one match per line instead of
printing all the matches. The subtle one is that if the pattern can
match in multiple overlapping positions, it will report the match with
the *latest* start instead of the *earliest* start (because the
leading .* is greedy).
The 'portable' solution that doesn't have those problems is to use a
nuke^W^Wperl:
perl -nle 'while(m((PATTERN))g){print $1}'
Philip Guenther
Re: gnu grep -o flag
Congratulations you found import! On Wed, Mar 24, 2010 at 02:52:31PM -0400, Brad Tilley wrote: No. i...@iso2:~/Desktop$ grep import IDS_targets.py import MySQLdb import socket import getpass import datetime i...@iso2:~/Desktop$ grep import -o IDS_targets.py import import import import On Wed, 24 Mar 2010 13:33 -0500, Marco Peereboom sl...@peereboom.us wrote: huh? didn't you just grep for that? On Wed, Mar 24, 2010 at 07:00:06PM +0200, Gregory Edigarov wrote: Hello Everybody, Just wonder how could one implement what gnu grep -o flag does using our toolchain? from ggrep(1): -o, --only-matching Show only the part of a matching line that matches PATTERN. -- With best regards, Gregory Edigarov
Re: gnu grep -o flag
On Wed, Mar 24, 2010 at 2010-03-24 21:13:40, Philip Guenther
guent...@gmail.com wrote: ...
Hmm, missing quote, and the expressions can be combined, but as a
portable solution this is indeed the right answer.
sed -n -e 's/.*\(PATTERN\).*/\1/p'
Actually, there are two bug in that, an obvious one and a subtle one.
The obvious one is that it only prints one match per line instead of
printing all the matches. The subtle one is that if the pattern can
match in multiple overlapping positions, it will report the match with
the *latest* start instead of the *earliest* start (because the
leading .* is greedy).
The 'portable' solution that doesn't have those problems is to use a
nuke^W^Wperl:
perl -nle 'while(m((PATTERN))g){print $1}'
Philip Guenther
I'm sure there is a case in which sed should be used instead of perl,
but I haven't run across it yet.
--
Edward Ahlsen-Girard
Ft Walton Beach, FL
