Linux in a Nutshell, Fifth Edition

crontab | 103

Linux

Commands

This is the Title of the Book, eMatter Edition

Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

currently defined. No additional tokens are permitted on the

directive line after name.

#if constant-expression

Lines following this directive and up to matching #endif or

next #else or #elif will appear in the output if constant-

expression evaluates to nonzero.

#elif constant-expression

An arbitrary number of #elif directives are allowed between

an #if, #ifdef,or#ifndef directive and an #else or #endif

directive. The lines following the #elif and up to the next

#else, #elif,or#endif directive will appear in the output if

the preceding test directive and all intervening #elif directives

evaluate to zero, and the constant-expression evaluates to

nonzero. If constant-expression evaluates to nonzero, all

succeeding #elif and #else directives will be ignored.

#else

Lines following this directive and up to the matching #endif

will appear in the output if the preceding test directive evalu-

ates to zero, and all intervening #elif directives evaluate to

zero. No additional tokens are permitted on the directive line.

#error

Report fatal errors.

#warning

Report warnings, but then continue processing.

crond

crond [options]

System administration command. Normally started in a system

startup file. Execute commands at scheduled times, as specified in

users’ files in /var/spool/cron ...