"unlimited: integer expression expected" error shown on install

Installed 6.5.0-1966 CE in a Docker container. At the end of installation, the following error appeared on console:

/opt/couchbase/bin/couchbase-server: line 72: [: unlimited: integer expression expected

The line in question reads:

if [ `ulimit $1` -lt $2 ]

 
which will fail in this way if "ulimit -u" (number of processes) or "ulimit -n" (number of open files) is set to "unlimited".