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You want to be able to collect STDOUT and/or STDERR text for logging purposes.
Use I/O direction to create your own log files.
In VMS, the batch job controller will automatically create a log
file containing all diagnostic messages generated by a DCL command
procedure and the commands it executes. The Unix
cron, at, and batch
commands are used for running programs and scripts in batch. By
default these batch utilities want to send e-mail instead of
creating a log file. Basically anything that would be sent to the
terminal is mailed to the job's owner instead. Knowing this, you can
control what is sent via e-mail as well as creating your own log
files by using I/O redirection.
Consider the following script where
myJob.pl is a
simple Perl program that writes a labeled line to both
STDOUT and STDERR.
#!/bin/sh
#
# File: cases.sh
# Abstract: Demo different types of redirection.
#
#=========
#---------------------------------------+
# STDOUT & STDERR to terminal. |
#---------------------------------------+
./myJob.pl "CASE 1"
#---------------------------------------+
# STDOUT to log. |
#---------------------------------------+
./myJob.pl "CASE 2" >case.2
#---------------------------------------+
# STDERR to log. |
#---------------------------------------+
./myJob.pl "CASE 3" 2>case.3
#---------------------------------------+
# STDOUT & STDERR to same log. |
#---------------------------------------|
# The order is important! Establish |
# the file first, *then* connect STDERR |
# to the same location as STDOUT. |
#---------------------------------------+
./myJob.pl "CASE 4" >case.4 2>&1
#---------------------------------------+
# STDOUT to log, pipe STDERR to another |
# program. |
#---------------------------------------|
# Swap STDOUT and STDERR, now errors |
# are coming out STDOUT instead and |
# thus can be piped. |
#---------------------------------------+
./myJob.pl "CASE 5" 3>&2 2>&1 1>&3 >case.5 | cat -net
#---------------------------------------+
# STDOUT & STDERR to same log *and* | "Multipexing multiple I/O streams
# STDERR to terminal. | is never a pretty picture."
#---------------------------------------| The Perl Cookbook.
# Label the data lines and take *all* |
# output and send it to STDOUT. Pipe |
# result to tee to save all in a file, |
# then filter tee's STDOUT to show only |
# the STDERR lines. The errors will |
# appear first in the log. |
#---------------------------------------+
(./myJob.pl "CASE 6" | sed -e 's/^/DATA: /' ) 2>&1 \
| tee case.6 \
| grep -v '^DATA: '
#==[ EOF: cases.sh ]==
Execution of this script sends the following output to the terminal:
unix> ./cases.sh
[CASE 1]: this is stdout
[CASE 1]: THIS IS STDERR
[CASE 2]: THIS IS STDERR
[CASE 3]: this is stdout
1 [CASE 5]: THIS IS STDERR$
[CASE 6]: THIS IS STDERR
unix>
unix> ls -la case.* -rw-rw---- 1 wfc users 25 Mar 13 23:20 case.2 -rw-rw---- 1 wfc users 25 Mar 13 23:20 case.3 -rw-rw---- 1 wfc users 50 Mar 13 23:20 case.4 -rw-rw---- 1 wfc users 25 Mar 13 23:20 case.5 -rw-rw---- 1 wfc users 56 Mar 13 23:20 case.6 unix> unix> cat case.2 [CASE 2]: this is stdout unix> cat case.3 [CASE 3]: THIS IS STDERR unix> cat case.4 [CASE 4]: THIS IS STDERR [CASE 4]: this is stdout unix> cat case.5 [CASE 5]: this is stdout unix> cat case.6 [CASE 6]: THIS IS STDERR DATA: [CASE 6]: this is stdout unix>
3.2 - Using STDERR and Exit Codes;
Chapter 2 of Unix for OpenVMS Users
;
Chapter 47 of Unix Power Tools
.
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This page maintained by: Bill.Costa@unh.edu of the Enterprise Computing Group in the dept of Computing & Information Sevices at the University of New Hampshire |
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