cron - perl search replace is appending not replacing -

i have perl script in cron runs every x minutes. suppose find string , replace string more data:

s/remote_phonebook.data.1.name =/remote_phonebook.data.1.name = users/;

i expect this:

before:

remote_phonebook.data.1.name =

after:

remote_phonebook.data.1.name = users

the first time runs works fine. however, each additional time appends end of line 3 cron jobs later see:

 remote_phonebook.data.1.name = users users users

how can make if "users" doesn't exist, add it, if exists, ignore?

if each 1 of these new line try:

$s =~ s/remote_phonebook\.data\.1\.name =( users|$)/remote_phonebook.data.1.name = users/;

if not, please let me know on comments.

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