#!/bin/bash
s="git@ssh.gitlab.org:repo1/dir/dir/file1.git
git@ssh.gitlab.org:repo1/dir/dir/file2.git
git@ssh.gitlab.org:repo1/dir/dir/file3.git
git@ssh.gitlab.org:repo1/dir/dir/file4.git"
awk -F':' '{sub(/\.[^.\/]*$/, "", $2); print $2;}' <<< "$s"
IyEvYmluL2Jhc2gKcz0iZ2l0QHNzaC5naXRsYWIub3JnOnJlcG8xL2Rpci9kaXIvZmlsZTEuZ2l0CmdpdEBzc2guZ2l0bGFiLm9yZzpyZXBvMS9kaXIvZGlyL2ZpbGUyLmdpdApnaXRAc3NoLmdpdGxhYi5vcmc6cmVwbzEvZGlyL2Rpci9maWxlMy5naXQKZ2l0QHNzaC5naXRsYWIub3JnOnJlcG8xL2Rpci9kaXIvZmlsZTQuZ2l0IgoKYXdrIC1GJzonICd7c3ViKC9cLlteLlwvXSokLywgIiIsICQyKTsgcHJpbnQgJDI7fScgPDw8ICIkcyI=