Telling tar not to traverse mount-points ?

[michaelsanford]

Slack 1 Exports:
/var/swaret (Swaret cache)
/var/sources (all my source codes)
/var/backup/slack1 (to keep backups)

Slack 2 Mounts:
/root/sources (from slack1:/var/sources)
/var/swaret_nfs (from slack1:/var/swaret)
/var/backup (from slack1:/var/backup/slack1)

I want to be able to issue:
/@slack2# tar cf root /var/backup/root.tar
/@slack2# tar cf var /var/backup/var.tar

But I can't because it duplicates tonnes of files (sources) or creates a loop (backing up /var to /var/backup/var.tar which contains /var/backup/var.tar). The problem, however, would be solved if I could tell tar not to traverse mount points. I'm /sure/ I've seen this option but man tar and tar --help didn't --help much

I would prefer to keep these mounted paths where they are but if I have to I can always mount them off a folder like /mounts/swaret or /mounts/backup

 

[michaelsanford]

Nevermind, I just got off my horse and put them all in /mnt/slack1

(The answer, if available, wouldn't hurt though )

 

[chornbe]

tar has an "--exclude" option, you can stack as many of them as you want on the command line.