Grep match percentage

Sefyir · 12-14-2015, 07:34 PM

I need to match a percentage from 0% to 100%

My current code will match from 10-99% but not 0-9% or 100%

Code:

grep [0-9][0-9]%

I'm trying to match a ping packet loss output.

Code:

ping www.domain.tld
PING domain.tld (64.xx.xxx.xx) 56(84) bytes of data.
64 bytes from domain.tld (64.xx.xxx.xx): icmp_req=1 ttl=52 time=45.6 ms 
64 bytes from domain.tld (64.xx.xxx.xx): icmp_req=2 ttl=52 time=47.5 ms 
64 bytes from domain.tld (64.xx.xxx.xx): icmp_req=4 ttl=52 time=45.0 ms 
64 bytes from domain.tld (64.xx.xxx.xx): icmp_req=6 ttl=52 time=46.0 ms 
^C64 bytes from domain.tld (64.xx.xxx.xx): icmp_req=7 ttl=52 time=47.2 ms 

--- domain.tld ping statistics ---
7 packets transmitted, 5 received, 28% packet loss, time 14375ms
rtt min/avg/max/mdev = 45.030/46.323/47.595/0.989 ms

example code in use:

Code:

ping -qc 10 domain.tld | grep -o '[0-9][0-9]%'

syg00 · 12-14-2015, 07:54 PM

You need extended regex - "grep -E". It allows you to define a varying range - {1,3}.

Hmm - just grep will do it too if you escape the curly brackets.

Sefyir · 12-14-2015, 08:13 PM

After a little more testing this works

Code:

grep -E '[0-9]|[0-9][0-9]|100'\

Had to use extended but that's ok. Escaping brackets didn't work for me using normal grep?

Code:

grep -E '[0-9]|[0-9][0-9]|100'\%

Matches 0-9%

Code:

grep -E '[0-9]|[0-9][0-9]|100'\%

Matches 10-99%

Code:

grep -E '[0-9]|[0-9][0-9]|100'\%

Matches 100%

Edit:
The above didn't match my original output (ping output) and matches a lot of extra stuff. This worked better with ping

Code:

grep -oE '[0-9]\%|[0-9][0-9]\%|100\%'

syg00 · 12-14-2015, 08:41 PM

Code:

grep -Eo "[[:digit:]]{1,3}%"
grep -o "[0-9]\{1,3\}%"

Sefyir · 12-14-2015, 09:07 PM

Quote:

Originally Posted by syg00

Code:

grep -Eo "[[:digit:]]{1,3}%"
grep -o "[0-9]\{1,3\}%"

That works - but I don't understand the role of {1,3}?

berndbausch · 12-14-2015, 09:16 PM

Quote:

Originally Posted by Sefyir

That works - but I don't understand the role of {1,3}?

It's just the count of digits - between one and three.
Technically this is not quite correct by the way - it would match 321% for example. Practically you are unlikely to encounter it though.

syg00 · 12-14-2015, 09:17 PM

Read the section on regex in the grep manpage.

JJJCR · 12-15-2015, 12:17 AM

Quote:

Originally Posted by Sefyir

That works - but I don't understand the role of {1,3}?

Curly Brackets
Curly brackets { } are general repetition quantifiers. They specify a minimum and maximum number of permitted matches.

{match the string if at least n times, match the string if not more than n times}

For example: a{2,4} matches aa, aaa, or aaaa, but not a or aaaaa

{n} - exactly n times

from this link: https://sc1.checkpoint.com/documents...uide/12885.htm