[SOLVED] if loop with multiple conditions

cnitin · 12-03-2012, 02:50 AM

Hi Friends,

i've written a bash script which checks a log file for error codes and then sends mail accordingly.

I have one if condition whose pseudo code would be like below

if $a = m or $a = n or $a = o
then
do something
else
do something
fi

Code:

if [[ "$input1" == "ORA-01555" ]] ||  [[ "$input1" == "ORA-12012" ]] || [[ "$input1" == "ORA-20001" ]] || [[ "$input1" == "ORA-06512" ]

however above seems to be not working , other than || i've also used "-o" in if condition.

Kindly help

colucix · 12-03-2012, 02:56 AM

Please, translate "above seems to be not working". It works for me. You can also put the logical OR inside the brackets:

Code:

if [[ "$input1" == "ORA-01555" ||  "$input1" == "ORA-12012" || "$input1" == "ORA-20001" || "$input1" == "ORA-06512" ]]
then
  echo do something
else
  echo do something else
fi

cnitin · 12-03-2012, 04:44 AM

Thanks Colucix,

i'm posting the code as below.

Code:

#!/bin/bash

expdate=`date '+%d_%m_%Y_%H_%M_%S'`

tail -300 /oraclehome/ora10g/admin/dbname/bdump/alert_dbname.log > /tmp/alrtdbname.log

> /tmp/errlinenum.txt
> /tmp/alrterr.txt

count=0
#Check the alert log for errors
while read inputline
        do
                echo $inputline > test1.txt
                count=$((count+1))
                input=`cat test1.txt`
                input1=`cat test1.txt |awk '{ print $1 }'`
                 if [[ "$input1" == "ORA-01555" || "$input1" == "ORA-12012" || "$input1" == "ORA-20001" || "$input1" == "ORA-06512" ]]
                then
                        echo "Error can be ignored as it is caused by an SQL statement or a JOB"
                        ##exit from script
                else
                        input2=`echo $input1 | cut -b -4`
                        if [[ "$input2" == "ORA-" ]]
                        then
                                echo "error found"
                                echo "Error at line number in errlinenum.txt "$count
                                errlinenum=$count
                                echo $errlinenum >> /tmp/errlinenum.txt
                        else
                                echo $input2 > /dev/null
                        fi
                fi
done < /tmp/alrtdbname.log

#Check if file is empty or not
if [ -s /tmp/errlinenum.txt ]
        then
                echo "Error in alertlog file at" $expdate

                while read inputline2
                        do
                        sed -n "$inputline2"p /tmp/alrtdbname.log >> /tmp/alrterr.txt
                done < /tmp/errlinenum.txt

       
        else
                echo "No error in alertlog file at" $expdate
fi

the if condition is not working as desired , it echoes

Code:

error found
Error at line number in errlinenum.txt <some number>

chrism01 · 12-04-2012, 06:54 PM

You still haven't define 'not working'
This will show you what its really doing

Code:

#!/bin/bash

#Tell parser to show us before and after version of each line
# and result
set -xv


<rest of your code>

David the H. · 12-05-2012, 09:29 PM

I see this thread is now marked as solved. I take it that the above suggestions worked for you then? General etiquette recommends that you should acknowledge it explicitly with a follow-up post.

I have a few additional suggestions concerning your script:

1) $(..) is highly recommended over `..`

2) QUOTE ALL OF YOUR VARIABLE EXPANSIONS. You should never leave the quotes off a parameter expansion unless you explicitly want the resulting string to be word-split by the shell (globbing patterns are also expanded). This is a vitally important concept in scripting, so train yourself to do it correctly now. You can learn about the exceptions later.

http://mywiki.wooledge.org/Arguments
http://mywiki.wooledge.org/WordSplitting
http://mywiki.wooledge.org/Quotes

When you have longer strings, the usual rule of thumb is to simply quote the longest string possible, including the variables.

Code:

#echo "Error at line number in errlinenum.txt "$count
echo "Error at line number in errlinenum.txt $count"

3) Avoid the Useless Use Of Cat. Tools like awk can generally accept files as direct arguments.

4) If your purpose is to test a single string against multiple conditions, a case statement is usually preferred over multiple ifs.

Code:

case $input1 in
	ORA-01555|ORA-12012|ORA-20001|ORA-06512)
		echo "Error can be ignored as it is caused by an SQL statement or a JOB"
	;;
	ORA-*) echo "error found"
		...
	;;
	*)  echo $input2 > /dev/null
	;;
esac

(What's the purpose of that last command, BTW, since it basically does nothing? If you need a placeholder command, use ":" (a synonym for the "true" command), or else just leave it out of the script.

5) If a string is already stored in a variable, it's usually recommended to use parameter substitution or other built-in string manipulation techniques, rather than external commands.

Code:

#input2=`echo $input1 | cut -b -4`
input2=${input1:0:4}

You can also use globbing patterns directly in double-bracket tests.

Code:

if [[ $input1 == ORA-* ]]

Although in this particular situation you should be able to just include the it in the enclosing case statement, as I demonstrated above.

6) When using bash or ksh, it's recommended to use [[..]] for string/file tests, and ((..)) for numerical tests. Avoid using the old [..] test unless you specifically need POSIX-style portability.

http://wiki.bash-hackers.org/commands/classictest
http://wiki.bash-hackers.org/syntax/...nal_expression
http://wiki.bash-hackers.org/syntax/arith_expr

I'm recommending this here particularly to highlight that you should be consistent in their use.

cnitin · 12-09-2012, 11:42 PM

Hi David and Chrism01 ,

It was just my own mistake

,

The output using awk was different than what i expected , and when i would compare it in if loop it would always turn false and the loop would end in else block.

when i tried awk on the logfile , i saw that the awk was returning "ORA-0512: " that colon was the whole issue , my mistake ..

Thanks a lot guys , and david and chrism01 ,the tips that you gave would sure be helpful to me in future.

have fun .