- f"nohup ./t-rex-64 " \
- f"--hdrh{u' --astf' if osi_layer == u'L7' else u''} " \
- f"--prefix $(hostname) -i -c 7 > /tmp/trex.log 2>&1 &\" > " \
- f"/dev/null"
+ f"nohup ./t-rex-64 -i -c {Constants.TREX_CORE_COUNT} --hdrh " \
+ f"{u' --astf' if osi_layer == u'L7' else u''} " \
+ f"--prefix $(hostname) {Constants.TREX_EXTRA_CMDLINE} " \
+ f"> /tmp/trex.log 2>&1 &\" > /dev/null"