nischttl Command

The nischttl command changes the time-to-live value of objects or entries in the namespace. This time-to-live value is used by the cache manager to determine when to expire a cache entry. You can specify the time-to-live in total number of seconds or in a combination of days, hours, minutes, and seconds.

The time-to-live values you assign objects or entries should depend on the stability of the object. If an object is prone to frequent change, give it a low time-to-live value. If it is steady, give it a high one. A high time-to-live is a week; a low one is less than a minute. Password entries should have time-to-live values of about 12 hours to accommodate one password change per day. Entries in tables that don't change much, such as those in the RPC table, can have values of several weeks.

To change the time-to-live of an object, you must have modify rights to that object. To change the time-to-live of a table entry, you must have modify rights to the table, entry, or columns you wish to modify.

To display the current time-to-live value of an object or table entry, use the nisdefaults -t command, described in Chapter 15, Administering NIS+ Access Rights.

To change the time-to-live value of objects, use:

nischttl time-to-live object-name

or

nischttl [-L] time-to-live object-name

To change the time-to-live value of entries, use:

nischttl time-to-live \
 [column=value,...], \
 table-name

or

nischttl [-ALP] time-to-live \
 [column=value,...], \
 table-name

Where time-to-live is expressed as:

• Number of seconds. A number with no letter is interpreted as a number of seconds. Thus, 1234 for TTL would be interpreted as 1,234 seconds. A number followed by the letter s is also interpreted as a number of seconds. Thus, 987s for TTL would be interpreted as 987 seconds. When seconds are specified in combination with days, hours, or minutes, you must use the letter s to identify the seconds value.

• Number of minutes. A number followed by the letter m is interpreted as a number of minutes. Thus, 90m for TTL would be interpreted as 90 minutes.

• Number of hours. A number followed by the letter h is interpreted as a number of hours. Thus, 9h for TTL would be interpreted as 9 hours.

• Number of days. A number followed by the letter d is interpreted as a number of days. Thus, 7d for TTL would be interpreted as 7 days.

These values may be used in combination. For example, a TTL value of 4d3h2m1s would specify a time to live of four days, three hours, two minutes, and one second.

The following flags may also be used with the nischttl command.

Table 18-6 nischttl Syntax Options

Changing the Time-to-Live of an NIS+ Object

To change the time-to-live of an object, type the nischttl command with the time-to-live value and the object-name. You can add the -L command to extend the change to linked objects.

nischttl -L time-to-live object-name

You can specify the time-to-live in seconds by typing the number of seconds. Or you can specify a combination of days, hours, minutes, and seconds by using the suffixes s, m, h, and d to indicate the number of seconds, minutes, days, and hours. For example:

client% nischttl 86400 sales.doc.com.
client% nischttl 24h sales.doc.com.
client% nischttl 2d1h1m1s sales.doc.com.

The first two commands change the time-to-live of the sales.doc.com. directory to 86,400 seconds, or 24 hours. The third command changes the time-to-live of all the entries in a hosts table to 2 days, 1 hour, 1 minute, and 1 second.

Changing the Time-to-Live of an NIS+ Table Entry

To change the time-to-live of entries, use the indexed entry format. You can use any of the options, -A, -L, or -P.

nischttl [-ALP] time-to-live \
 [column=value,...], \
 table-name

These examples are similar to those above, but they change the value of table entries instead of objects:

client% nischttl 86400 '[uid=99],passwd.org_dir.doc.com.'
client% nischttl 24h `[uid=99],passwd.org_dir.doc.com.'
client% nischttl 2d1h1m1s `[name=fred],hosts.org_dir.doc.com.'