#!/bin/bash
string1="userbasedn:DC=i,DC=companyname,DC=com?subtree?(&(objectcategory=person)(uidNumber=*)(|(memberOf:1.2.840.113556.1.4.1941:=cn=example1,OU=GROUPS,OU=INFRASTRUCTURE,DC=i,DC=companyname,DC=com)(memberOf:1.2.840.11.1.4.1941:=cn=example2,OU=GROUPS,OU=INFRASTRUCTURE,DC=i,DC=companyname,DC=com)))
groupbasedn:DC=i,DC=companyname,DC=com?subtree?(&(objectcategory=group)(gidNumber=*))"
mapfile -t arr < <(grep -oE 'cn=[^()]*DC=com' <<< "$string1")
declare -p arr
printf '%s\n' "${arr[@]}"
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
declare -a arr=([0]="cn=example1,OU=GROUPS,OU=INFRASTRUCTURE,DC=i,DC=companyname,DC=com" [1]="cn=example2,OU=GROUPS,OU=INFRASTRUCTURE,DC=i,DC=companyname,DC=com")
cn=example1,OU=GROUPS,OU=INFRASTRUCTURE,DC=i,DC=companyname,DC=com
cn=example2,OU=GROUPS,OU=INFRASTRUCTURE,DC=i,DC=companyname,DC=com