The parameter list include the following example values

# echo $list
master01.montil131.com worker01.montil131.com worker02.montil131.com

In order to find the word that include master string I do the following

list=$( for i in ` echo  $list `; do [[ $i =~ master ]] && echo $i ; done )

echo $list

but this approach to find the string with master word isn't elegant way

Any other suggestion how to find specific word in list ?

  • is $list a variable that contains the string "master01.montil131.com worker01.montil131.com worker02.montil131.com" ? a space separated list of words stored in a variable? – glenn jackman Feb 19 at 15:16
  • just one space between words ( no other comma separator )' – yael Feb 19 at 15:17
  • Unrelated: Why do you store a list in a string? It would be better to have it in an array... – Kusalananda Feb 19 at 20:55

Why not use simple grep command, I am assuming there are no spaces in a word in the list.

 echo $list | tr ' ' '\n' | grep master

It will replace space with new line and will then grep word master.


Use grep -o:

grep -o "[^ ]*master[^ ]*" <<<"$list"

If you know that you always have just master* and worker*, you can use Shell methods:

echo "${list// *worker[^ ]*/}"
grep -ow 'master[^ ]*' <<<"$list"

or, with GNU grep,

grep -Pow 'master\S+' <<<"$list"

The -o would extract the matching bit of the string in $list, and -w would ensure that we don't match themaster or some other word that does not start with master.

The \S in the second command is a PCRE that will match any non-space character.

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