How to extract a substring from a string using a string match condition in SHELL

Question

I have to extract a substring from this.

- Session establishment complete on server localhost/127.0.0.1:2183, sessionid = 
   0x1000c22ff510020, negotiated timeout = 120000 WATCHER:: WatchedEvent state:SyncConnected 
   type:None path:null [zk: localhost:2183(CONNECTED) 0] addauth digest super:testing [zk: 
   localhost:2183(CONNECTED) 1] ls /live_nodes [rn3-gcs02.rno.foo.com:8985_solr, rn3- 
   gcsb.rno.foo.com:8985_solr] [zk: localhost:2183(CONNECTED) 2]

The substring to be extracted is

[rn3-gcs02.rno.foo.com:8985_solr, rn3- gcsb.rno.foo.com:8985_solr]

it's a dynamic substring which can have 2 or more elements

Determined how? Just always whatever comes after `ls /live-nodes`? — Charles Duffy, May 08 '20 at 17:52
Also, are the linebreaks real/important, or can the whole thing just be coalesced into one line before doing any matching? — Charles Duffy, May 08 '20 at 17:52
BTW, note that in general, you're expected to show what you tried and what specific problem you had while making that attempt in asking a question. — Charles Duffy, May 08 '20 at 17:56
alwys comes after ls /live-nodes. line breaks are not real. its single string line — Telen, May 08 '20 at 18:17

score 1 · Accepted Answer · answered May 08 '20 at 17:54

1

re='ls /live_nodes (\[[^]]+\])'
[[ $s =~ $re ]] && echo "${BASH_REMATCH[1]}"

...emits, with your input in $s:

[rn3-gcs02.rno.foo.com:8985_solr, rn3-
   gcsb.rno.foo.com:8985_solr]

answered May 08 '20 at 17:54

Charles Duffy

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How to extract a substring from a string using a string match condition in SHELL

1 Answers1