NAME
batch — execute
commands when the system load permits
SYNOPSIS
batch |
DESCRIPTION
The batch utility reads commands to be
executed at a later time. It is the equivalent of the command:
at -q b -m now
batch .
Users are permitted to use
batch if their name appears in the file
/usr/lib/cron/at.allow.
If that file does not exist, the file
/usr/lib/cron/at.deny.
is checked to determine if the user should be denied access to
batch. If neither file exists, only a process with
the appropriate privileges is allowed to submit a job. If only
at.denyat.allow
and
at.deny
files consist of one user name per line.
OPTIONS
None.
OPERANDS
None.
STDIN
The standard input must be a text file consisting of commands
acceptable to the shell command language described in Shell Command Language
. The standard input will only be used if no -f file
option is specified.
INPUT FILES
The text files /usr/lib/cron/at.allow and /usr/lib/cron/at.deny
contain user names, one per line, of users who are, respectively, authorised
or denied access to the at(1) and
batch utilities.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of
batch :
LANG- Provide a default value for the internationalisation variables that are
unset or null. If
LANGis unset or null, the corresponding value from the implementation-dependent default locale will be used. If any of the internationalisation variables contains an invalid setting, the utility will behave as if none of the variables had been defined. LC_ALL- If set to a non-empty string value, override the values of all the other internationalisation variables.
LC_CTYPE- Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single- as opposed to multi-byte characters in arguments and input files).
LC_MESSAGES- Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error and informative messages written to standard output.
LC_TIME- Determine the format and contents for date and time strings written by
batch. NLSPATH- Determine the location of message catalogues for the processing of LC_MESSAGES .
SHELL- Determine the name of a command interpreter to be used to invoke the at-job. If the variable is unset or null, sh(1) will be used. If it is set to a value other than a name for sh(1) , the implementation will do one of the following: use that shell; use sh(1) ; use the login shell from the user database; any of the preceding accompanied by a warning diagnostic about which was chosen.
TZ- Determine the timezone. The job will be submitted for execution at the
time specified by timespec or
-ttime relative to the timezone specified by theTZvariable. If timespec specifies a timezone, it will override TZ . If timespec does not specify a timezone andTZis unset or null, an unspecified default timezone will be used.
ASYNCHRONOUS EVENTS
Default.
STDOUT
When standard input is a terminal, prompts of unspecified format for each line of the user input described in the STDIN section may be written to standard output.
In the POSIX locale, the following will be written to the standard
output for each job when jobs are listed in response to the
-l option:
"%s\t%s\n",
at_job_id, <
date > where < date > is
equivalent in format to the output of: date +"%a %b %e
%T %Y"
The date and time written will be adjusted so that they appear in the timezone of the user (as determined by the TZ variable).
STDERR
The following will be written to standard error when a job has been successfully submitted:
"job %s at %s\n", at_job_id,
<date> where < date > will have the
same format as is described in the STDOUT section. Neither this, nor warning
messages concerning the selection of the command interpreter, are considered
a diagnostic that changes the exit status.
Diagnostic messages, if any, are written to standard error.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values are returned:
CONSEQUENCES OF ERRORS
The job will not be scheduled.
APPLICATION USAGE
It may be useful to redirect standard output within the specified commands.
EXAMPLES
- This sequence can be used at a terminal:
batch sort < file >outfile EOT
- This sequence, which demonstrates redirecting standard error to a pipe, is
useful in a command procedure (the sequence of output redirection
specifications is significant):
batch <<! diff file1 file2 2>&1 >outfile | mailx mygroup !
FUTURE DIRECTIONS
None.
SEE ALSO
at(1) .