Grep for multiple words and phrases

English Applications
#1

I am writing some code. I want to extract from “ifconfig” the device names and IP addresses. For example this expression will get me a result I want:

ifconfig | egrep "Ethernet|Bcast"

Here is the output:

ath0 Link encap:Ethernet HWaddr 00:17:9A:75:CA:A6
inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.255.0

Then I got to thinking: how do I cope with phrases (in the future). For example what would be the grep command to return lines containing the phrases ‘Ethernet HW’ and ’ Bcast’ (that’s Bcast with a space in front of it)?

I need phrases because I want to grep files like smb.conf for lines containing phrases like these:
name resolve order
netbios name
map to guest

I’ve looked at ‘man grep’ and it just leaves me confused for this level of detail.

Thanks

#2

Pretty much what you are doing … if, from your example where you want (space)Bcast and Ethernet(space)(space)HW, you would do:

ifconfig|egrep "Ethernet  HW| Bcast"
eth0      Link encap:Ethernet  HWaddr 00:19:D1:81:D6:2E
          inet addr:192.168.2.119  Bcast:192.168.2.255  Mask:255.255.255.0

So put the exact phrases within double quotes like you are doing and it should work fine.

#3

Understanding regular expressions, regexps or REs are the key to grep and other uses of REs. Here are a couple of links to get you started:

Regular expression - Wikipedia, the free encyclopedia
Regular-Expressions.info - Regex Tutorial, Examples and Reference - Regexp Patterns

Then you can tackle the options that grep offers.

As a hint, you would need something like:

grep -i ‘name +resolve +order’

  • is the once or more times operator.

If you are dealing with multiline options, it might be easier to write the program in Perl.

#4

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Doesn’t your existing output already have a space at the beginning? It
surely seems to based on your output. Anyway, grep doesn’t care about a
space before what it finds (at least in your case) because of how the
regex is setup. You can force no-space before/after some other pattern
but in your case it is not done so it is not enforced.

Good luck.

swerdna wrote:
> I am writing some code. I want to extract from “ifconfig” the device
> names and IP addresses. For example this expression will get me a result
> I want:
>
> Code:
> --------------------
> ifconfig | egrep “Ethernet|Bcast”
> --------------------
>
> Here is the output:
>> ath0 Link encap:Ethernet HWaddr 00:17:9A:75:CA:A6
>> inet addr:192.168.1.2 Bcast:192.168.1.255
>> Mask:255.255.255.0
>
> Then I got to thinking: how do I cope with phrases (in the future). For
> example what would be the grep command to return lines containing the
> phrases ‘Ethernet HW’ and ’ Bcast’ (that’s Bcast with a space in front
> of it)?
>
> I need phrases because I want to grep files like smb.conf for lines
> containing phrases like these:
> name resolve order
> netbios name
> map to guest
>
> I’ve looked at ‘man grep’ and it just leaves me confused for this level
> of detail.
>
> Thanks
>
>
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#5

[QUOTE=swerdna]
I am writing some code. I want to extract from “ifconfig” the device
names and IP addresses. For example this expression will get me a result
I want:

Code:

ifconfig | egrep “Ethernet|Bcast”

Here is the output:
> ath0 Link encap:Ethernet HWaddr 00:17:9A:75:CA:A6
> inet addr:192.168.1.2 Bcast:192.168.1.255
> Mask:255.255.255.0

Then I got to thinking: how do I cope with phrases (in the future). For
example what would be the grep command to return lines containing the
phrases ‘Ethernet HW’ and ’ Bcast’ (that’s Bcast with a space in front
of it)?

I need phrases because I want to grep files like smb.conf for lines
containing phrases like these:
name resolve order
netbios name
map to guest

I’ve looked at ‘man grep’ and it just leaves me confused for this level
of detail.

Thanks
/QUOTE]
Hi
This should give you a list of all the active options


grep -v ^# <your conf file> | grep -v ^$

I’m guessing awk, sed will probably refine it more… man bash, then;


man bash
/regex<enter>

I use perl, so much easier :slight_smile:

–
Cheers Malcolm °¿° (Linux Counter #276890)
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#6

Well thankyou all. Don’t know why I didn’t think of the “excat phrase|another phrase” version. OK got it now e.g.

john@suse110:~> cat /etc/samba/smb.conf | grep -E “name resolve order|netbios name|local master”
netbios name = suse110
name resolve order = bcast host lmhosts wins
local master = yes

What a hoot!

The other suggestions I’m tracking down as we speak.
Regarding perl and other scripts: eventually I want to make available software to others so I need it to be not dependent on them having to install scripting language/s. So I’m writing in a compilable language → independent executable file.

Thanks again.

#7

swerdna wrote:
> I am writing some code.

maybe help is also available if posted in (or moved to) the
programming-scripting forum…

ideally follow-on folks looking for a similar answer should look
there, instead of here…

–
see caveat: http://tinyurl.com/6aagco
DenverD (Linux Counter 282315) via NNTP, Thunderbird 2.0.0.14, KDE
3.5.7, SUSE Linux 10.3, 2.6.22.18-0.2-default #1 SMP i686 athlon

#8

Thanks for that, but I think it should be with “Applications” because it’s a question about a Linux app (grep, egrep).