xref: /freebsd/usr.sbin/cron/doc/CONVERSION (revision cfd6422a5217410fbd66f7a7a8a64d9d85e61229)
1$FreeBSD$
2
3Conversion of BSD 4.[23] crontab files:
4
5Edit your current crontab (/usr/lib/crontab) into little pieces, with each
6users' commands in a different file.  This is different on 4.2 and 4.3,
7but I'll get to that below.  The biggest feature of this cron is that you
8can move 'news' and 'uucp' cron commands into files owned and maintainable
9by those two users.  You also get to rip all the fancy 'su' footwork out
10of the cron commands.  On 4.3, there's no need for the 'su' stuff since the
11user name appears on each command -- but I'd still rather have separate
12crontabs with separate environments and so on.
13
14Leave the original /usr/lib/crontab!  This cron doesn't use it, so you may
15as well keep it around for a while in case something goes wakko with this
16fancy version.
17
18Most commands in most crontabs are run by root, have to run by root, and
19should continue to be run by root.  They still have to be in their own file;
20I recommend /etc/crontab.src or /usr/adm/crontab.src.
21
22'uucp's commands need their own file; how about /usr/lib/uucp/crontab.src?
23'news' also, perhaps in /usr/lib/news/crontab.src...
24
25I say `how about' and `perhaps' because it really doesn't matter to anyone
26(except you) where you put the crontab source files.  The `crontab' command
27COPIES them into a protected directory (CRONDIR/SPOOL_DIR in cron.h), named
28after the user whose crontab it is.  If you want to examine, replace, or
29delete a crontab, the `crontab' command does all of those things.  The
30various `crontab.src' (my suggested name for them) files are just source
31files---they have to be copied to SPOOLDIR using `crontab' before they'll be
32executed.
33
34On 4.2, your crontab might have a few lines like this:
35
36	5 * * * *   su uucp < /usr/lib/uucp/uudemon.hr
37	10 4 * * *  su uucp < /usr/lib/uucp/uudemon.day
38	15 5 * * 0  su uucp < /usr/lib/uucp/uudemon.wk
39
40...or like this:
41
42	5 * * * *   echo /usr/lib/uucp/uudemon.hr | su uucp
43	10 4 * * *  echo /usr/lib/uucp/uudemon.day | su uucp
44	15 5 * * 0  echo /usr/lib/uucp/uudemon.wk | su uucp
45
46On 4.3, they'd look a little bit better, but not much:
47
48	5 * * * *   uucp  /usr/lib/uucp/uudemon.hr
49	10 4 * * *  uucp  /usr/lib/uucp/uudemon.day
50	15 5 * * 0  uucp  /usr/lib/uucp/uudemon.wk
51
52For this cron, you'd create /usr/lib/uucp/crontab.src (or wherever you want
53to keep uucp's commands) which would look like this:
54
55	# /usr/lib/uucp/crontab.src - uucp's crontab
56	#
57	PATH=/usr/lib/uucp:/bin:/usr/bin
58	SHELL=/bin/sh
59	HOME=/usr/lib/uucp
60	#
61	5 * * * *   uudemon.hr
62	10 4 * * *  uudemon.day
63	15 5 * * 0  uudemon.wk
64
65The application to the `news' cron commands (if any) is left for you to
66figure out.  Likewise if there are any other cruddy-looking 'su' commands in
67your crontab commands, you don't need them anymore: just find a good place
68to put the `crontab.src' (or whatever you want to call it) file for that
69user, put the cron commands into it, and install it using the `crontab'
70command (probably with "-u USERNAME", but see the man page).
71
72If you run a 4.2-derived cron, you could of course just install your current
73crontab in toto as root's crontab.  It would work exactly the way your
74current one does, barring the extra steps in installing or changing it.
75There would still be advantages to this cron, mostly that you get mail if
76there is any output from your cron commands.
77
78One note about getting mail from cron: you will probably find, after you
79install this version of cron, that your cron commands are generating a lot
80of irritating output.  The work-around for this is to redirect all EXPECTED
81output to a per-execution log file, which you can examine if you want to
82see the output from the "last time" a command was executed; if you get any
83UNEXPECTED output, it will be mailed to you.  This takes a while to get
84right, but it's amazingly convenient.  Trust me.
85
86