Suppose you have a directory /pub/gitlab with all your git projects, but also a logs directory which can be skipped.

user@server:~$ cat > cleanall
cd /pub/gitlab
for d in */ ; do
log=$(basename $d)
[[ $log =~ ^(logs)$ ]] && continue
cd "$d"
echo -n "$d : "
mvn clean
cd ..
done

user@server:~$ cat > pullall
cd /pub/gitlab
for d in */ ; do
log=$(basename $d)
[[ $log =~ ^(logs)$ ]] && continue
cd "$d"
echo -n "$d : "
git pull
cd ..
done