harold$ cat -n app_system.log.7 | grep -E 'period' | cut -f 1 | while read x; do head -$x app_system.log.7 | tail -2
15-APR-2004 10:49:03 PI-I-PI_Log_Report_Period
Report period 01/01 00:00 - 04/15 23:59. From time 1072933200 to 1082087940.
15-APR-2004 10:49:54 PI-I-PI_Log_Report_Period
Report period 01/01 00:00 - 04/15 23:59. From time 1072933200 to 1082087940.
15-APR-2004 12:54:30 PI-I-PI_Log_Report_Period
Report period 01/01 00:00 - 04/15 23:59. From time 1072933200 to 1082087940.
15-APR-2004 12:54:59 PI-I-PI_Log_Report_Period
Report period 01/01 00:00 - 04/15 23:59. From time 1072933200 to 1082087940.
15-APR-2004 12:55:32 PI-I-PI_Log_Report_Period
Report period 01/01 00:00 - 04/15 23:59. From time 1072933200 to 1082087940.
When run from my perl script I get this because $x is null (I think):
harold$ /home/harold/bin/search.pl Usage: head [-Count | -n Number | -c Number] [File...] Usage: head [-Count | -n Number | -c Number] [File...] Usage: head [-Count | -n Number | -c Number] [File...] Usage: head [-Count | -n Number | -c Number] [File...] Usage: head [-Count | -n Number | -c Number] [File...]
Jayakumar Rajagopal wrote:
Harold, (bottom posted)
-----Original Message----- From: hdan [mailto:[EMAIL PROTECTED] Sent: Thursday, April 22, 2004 1:54 PM To: Jayakumar Rajagopal Cc: hdan; [EMAIL PROTECTED] Subject: Re: backtick variable substitution
Thanks. I've tried that, but it didn't work. I've also tried using exec and system instead of backticks. I tried using eval, too, although I wasn't sure where to put it in the statement.
-harold
Jayakumar Rajagopal wrote:
Hi hdan,
try \$ for $.
I did not test it anyway.
HTH,
Jay
-----Original Message-----
From: hdan [ mailto:[EMAIL PROTECTED]
Sent: Thursday, April 22, 2004 1:13 PM
To: [EMAIL PROTECTED]
Subject: backtick variable substitution
Hi all,
Hopefully someone can help me out with this one.
I have a perl script that runs rsh commands to monitor a remote server.
To minimize time and bandwidth I need to maximize the processing that is
done on the remote server and minimize the number of rsh commands done.
My question is, how can I place a while loop within a system call so
that the loop variable is substituted correctly? Here is an example:
$THE_ERRORS =
`rsh remote_box "cat -n app_error.log | grep -E 'error' |
cut -f 1 | while read x; do head -$x app_error.log | tail -2; done"`;
Basically, I'm trying to get the error message line and the line before
it returned into $THE_ERRORS. The problem is that $x is not being
interpreted correctly by the head command.
For simplicity, we can take the whole rsh out of the picture and use
this as an example:
$THE_ERRORS =
`cat -n app_error.log | grep -E 'error' |
cut -f 1 | while read x; do head -$x app_error.log | tail -2; done`;
Thanks for any suggestions.
[Jayakumar Rajagopal] +++++++++++++++++++++++
Please let me know if you can run whatever inside the backticks in shell ( unix prompt).
Jay
