UNIX for Dummies Questions & Answers

Hi Everyone,
I am a bit new at learning this bash syntax. I have a problem at work that needs to be addressed. We find we are spending quite a bit of time killing old processes created by oracle replication that have been restarted later in the week. Because the replication takes time to complete (in days) I want to kill those processes that are 4 days and older.

I found this bit of code that will work just fine but I can’t seem to hook it up to my ps statement and I am at a loss as how to do this.
NOTE: the grep word “hald” is actually one of the linux processes. Something to work with.
There are two variables the first one (print $2) is the pid and the second is the date ($9). The numbers 2 and 9 are the columns numbered left to right. That output looks like this:

Code:

[root@localhost script]# ps aux | grep -i "hald" | awk '{print $2 "   " $9}'
1958   10:56
1959   10:56
1999   10:56
2004   10:56
4729   13:39

I am trying to pass in the date ($9) to the “todate” but am getting confused with the available formatting.
Once I get this to work returning the number of days then I can test it and issue the kill command for the associated pid ($2).

Running the code alone with the dates already there works fine.
The default date format is the following: Tue Oct 2 14:04:31 PDT 2012 . All I want is the day which is represented by date +%d and this returns 02. How can I represent $9 as date +%d ??
Any reference book recommended for reading would be appreciated.

Code:

#!/bin/sh
ps aux | grep -i "hald" | awk '{print $2 " " $9}'  
|
fromdate=01.04.2010
todate=24.05.2010
from=`echo $fromdate | awk  -F\. '{print $3$2$1}'`
to=`echo $todate | awk  -F\. '{print $3$2$1}'`
START_DATE=`date --date=$from +"%s"`
END_DATE=`date --date=$to +"%s"`
DAYS=$((($END_DATE - $START_DATE) / 86400 ))
echo $DAYS

Moderator's Comments:

Please use code tags, avoid odd font settings thanks.

Code:

#!/bin/sh
tdate=$(date +%Y%m%d)
psdate=$(ps aux | grep -i "hald" | grep -v grep | awk -v tdate=$tdate '$NF ~ /^hald$/ {if ($9 ~ ":") $9=tdate; print $9;}')
fromdate=01.04.2010
#todate=24.05.2010
from=`echo $fromdate | awk  -F\. '{print $3$2$1}'`
#to=`echo $todate | awk  -F\. '{print $3$2$1}'`
START_DATE=`date --date=$from +"%s"`
END_DATE=`date --date=$psdate +"%s"`
DAYS=$((($END_DATE - $START_DATE) / 86400 ))
echo $DAYS

Good Morning,

Thank you for the quick response. All this bash scripting is new to me so I will go over in great detail what was just written to understand this code. I need to get this stuff in my head and the only way to do it for me is just to "do it". I appreciate you being a mentor.

I will let you know how it runs.

regards,

al

---------- Post updated at 07:20 AM ---------- Previous update was at 06:52 AM ----------

Good Morning,

I am reading the code over and I did some research on the portion | grep -v grep|. The formula is grep pattern filename1 filename2.

I can't seem to understand why this is done nor where the -v is coming from.

A brief explanation would be appreciated.

thanks

al

Code:

ps aux | grep -i "hald"

Will print the grep in output.

-v : print all lines that don't match the pattern

try man grep