This operation is performed with the edquota command (man edquota for details).
I would normally run quotacheck with the flags -avug to obtain the most updated filesystems usage prior to editing quota. This is just a personal habit, and not a required step however.
Here's an example. I have a user with the login id bob on my system. The command "edquota -u bob" takes me into vi (or editor specified in my $EDITOR environment variable) to edit quota for user bob on each partition that has quota enabled:
Quotas for user bob:
/dev/hda2: blocks in use: 2594, limits (soft = 5000, hard = 6500)
inodes in use: 356, limits (soft = 1000, hard = 1500)
"blocks in use" is the total number of blocks (in kilobytes) a user has comsumed on a partition.
"inodes in use" is the total number of files a user has on a partition.
Now I have a group games on my system. "edquota -g games" takes me into the vi editor again to edit quota for the group games:
Quotas for group games:
/dev/hda4: blocks in use: 5799, limits (soft = 8000, hard = 10000)
inodes in use: 1454, limits (soft = 3000, hard = 4000)
To rapidly set quotas for, say 100 users, on my system to the same value as my user bob, I would first edit bob's quota information by hand, then execute:
edquota -p bob `awk -F: '$3 > 499 {print $1}' /etc/passwd`
assuming that you are using csh, and that you assign your user UID's starting with 500.
In addition to edquota, there are 3 terms which you should familiarize yourself with: Soft Limit, Hard Limit, and Grace Period.
_Soft limit_ indicates the maximum amount of disk usage a quota user has on a partition. When combined with grace period, it acts as the border line, which a quota user is issued warnings about his impending quota violation when passed.
Hard limit works only when grace period is set. It specifies the absolute limit on the disk usage, which a quota user can't go beyond his hard limit.
Executed with the command "edquota -t", grace period is a time limit before the soft limit is enforced for a file system with quota enabled. Time units of sec(onds), min(utes), hour(s), day(s), week(s), and month(s) can be used. This is what you'll see with the command "edquota -t":
Time units may be: days, hours, minutes, or seconds Grace period before enforcing soft limits for users: /dev/hda2: block grace period: 0 days, file grace period: 0 days
Change the 0 days part to any length of time you feel reasonable. I personally would choose 7 days (or 1 week).