Here's a one-liner that doesn't use/require the new job to be in a file:
(crontab -l 2>/dev/null; echo "*/5 * * * * /path/to/job -with args") | crontab -
The 2>/dev/null
is important so that you don't get the no crontab for username
message that some *nixes produce if there are currently no crontab entries.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…