if elif control issue

Shell Programming and Scripting
1

The below script is been ran on MYSQL database.... but control is not reaching to MYSQL elif block :wall:

The complete code is:

#!/usr/bin/ksh
 
MR=eml_msp131233
 
start=`date +%s%N`
 
echo "***Clean-up for Static Tables removal***" | tee  /tmp/$MR.log
 
        set -A mname1 "'"XYZ_100"'"        
 
echo "DB_SYSTEM =$DB_SYSTEM " | tee -a /tmp/$MR.log
if [ $DB_SYSTEM = "ORACLE" ] 
then
    echo "Deleting the entry table" | tee -a /tmp/$MR.log
        sqlplus -s $OPMDB_USR/$OSMDB_PWD <<!
        delete from xyz where modelname IN (${mname1[@]}); 
        commit;                
    exit
        !    
        echo "**** Required Model Names XYZ Deleted****" | tee -a /tmp/$MR.log
    i=0
    len=0
    len=${#port_add_tab
[*]}
    while [ $i -lt $len ]
    do         
               sqlplus -s $OPMDB_USR/$OSMDB_PWD << !
               drop table ${port_add_tab}; 
               exit
        !
       echo "****Table: ${port_add_tab} is deleted****" | tee -a /tmp/$MR.log
       i=`expr $i + 1`
    done
elif [ $DB_SYSTEM = "MYSQL" ] 
then    
    echo "Deleting the entry in Tables" | tee -a /tmp/$MR.log
        mysql --user=${OPMDB_USR} --password=${OPMDB_PWD} ${DB_NAME} << ! |tee -a /tmp/$MR.log       
        set storage_engine=INNODB;
        delete from XYZ where modelname IN (${mname1[@]}); 
        commit;             
    exit
!
        echo "**** Required Model XYZ Deleted****" | tee -a /tmp/$MR.log
    i=0
    len=0
    len=${#port_add_tab
[*]}
    while [ $i -lt $len ]
        do    
           mysql --user=${OPMDB_USR} --password=${OPMDB_PWD} ${DB_NAME} << ! | tee -a /tmp/$MR.log       
           set storage_engine=INPODB;
           drop table if exists ${port_add_tab}; 
           exit
!
           echo "****Table: ${port_add_tab} is deleted****" | tee -a /tmp/$MR.log
       i=`expr $i + 1`
       done
fi
 
end=`date +%s%N`
dif=$(($end - $start))
 
echo "Execution time in : $dif" | tee -a /tmp/$MR.log
echo "Done!! Script Executed successfully" | tee -a /tmp/$MR.log

Please help me....
please see the exe below:

+ MR=eml_msp131233
+ + date +%s%N
start=132367757620
+ echo ***This script is used for Migration Clean-up for Static Tables removal***
+ tee /tmp/eml_msp131233.log
***This script is used for DB Migration Clean-up for Static Tables removal***
+ set -A mname1 'XYZ_100'
+ echo DB_SYSTEM =MYSQL 
+ tee -a /tmp/eml_msp131233.log
DB_SYSTEM =MYSQL 
+ [ MYSQL = ORACLE ]
+ + date +%s%N
end=132367757620
+ dif=0
+ echo Execution time in : 0
+ tee -a /tmp/eml_msp131233.log
Execution time in : 0
+ echo Done!! Script Executed successfully
+ tee -a /tmp/eml_msp131233.log
Done!! Script Executed successfully
+ echo Please check the log in /tmp/eml_msp131233.log
2

It is reaching the block:

+ [ MYSQL = ORACLE ]

but it does not evaluate to true. In other words, "MYSQL" is not "ORACLE".

Check where and how the variable $DB_SYSTEM is set. It seems not in this script.

3

That is right zaxxon... MYSQL is not ORACLE...but then it should come to elif part it is not reaching there... that is the only problem:wall:

Seeking for further response....

Thanks, Ambar

4

You did not understand. Your code is

elif [ $DB_SYSTEM = "MYSQL" ]

The debugging output of this test is

+ [ MYSQL = ORACLE ]

So everything is going right. It only enters the elif block if the condition is true, which is not the case and so skips the elif block. If this is really a MYSQL system, then your variable seems to have a wrong value, wherever it is set.

5

The above is the output of the first test. i.e if [ $DB_SYSTEM = "ORACLE" ]
Even if the value of $DB_SYSTEM is set wrongly, the shell should evaluate (true/false) the elif block just like first "if" which is not happening in this case.

Something seems to be wrong.
OP also echo'ing the value of $DB_SYSTEM which seems to be interpreted correctly with the below line.

+ echo DB_SYSTEM =MYSQL 
+ tee -a /tmp/eml_msp131233.log
DB_SYSTEM =MYSQL

However, the value seems to have trailing white space, the test should ignore that because there is no quotes in the variable at the time of evaluation.

Sorry if I did not understand zaxxon's explanation.

6

You are right, sorry, my fault. Not sure what I read there.

7

Thanks zaxxon for your time; and also Thanks to make me understand the debug pattern. I have some how corrected my code :D.

Afterwards I realize there was issue with formatting/indentation also in the code...

if [ $DB_SYSTEM = "ORACLE" ]

i.e.

if [ $DB_SYSTEM="ORACLE" ]

I request if possible... can you please built some logical understanding for me in UNIX shell script indentation ...

Thanks again!!
Ambar Agrawal

---------- Post updated at 04:18 PM ---------- Previous update was at 04:11 PM ----------

Thanks Anchal, Yes problem seems with indentation in the script --

If []

Condition.

---------- Post updated at 04:38 PM ---------- Previous update was at 04:18 PM ----------

The below code ran fine now... Though I have given spaces between the '=' sign in the "IF Condition":

#!/usr/bin/ksh
MR=eml_msp131233
 
start=`date +%s%N`
i=0
len=0
 
echo "***Clean-up for Static Tables removal***" | tee  /tmp/$MR.log
 
        set -A mname1 "'"XYZ_100"'"        
echo "DB_SYSTEM =$DB_SYSTEM " | tee -a /tmp/$MR.log
 
if [ $DB_SYSTEM = "ORACLE" ]
then
    sqlplus -s $OSMDB_USR/$OSMDB_PWD<<!
     delete from pqr where modelname IN (${mname1[@]}); 
        commit;          
    exit
!
   echo "**** MY SQL Required Model Names Deleted****" | tee -a /tmp/$MR.log    
    len=${#port_add_tab
[*]}
    while [ $i -lt $len ]
        do    
           mysql --user=${OPMDB_USR} --password=${OPMDB_PWD} ${DB_NAME} << ! | tee -a /tmp/$MR.log       
           set storage_engine=IPNODB;
           drop table if exists ${port_add_tab}; 
           exit
!
           echo "****Table: ${port_add_tab} is dropped****" | tee -a /tmp/$MR.log
       i=`expr $i + 1`
       done
elif [ $DB_SYSTEM = "MYSQL" ]
then
    echo "hiiiiiii" | tee -a /tmp/$MR.log
    echo "Deleting the entry in  table" | tee -a /tmp/$MR.log
        mysql --user=${OSMDB_USR} --password=${OSMDB_PWD} ${DB_NAME} << ! |tee -a /tmp/$MR.log       
        set storage_engine=INNODB;
        delete from XYZ where modelname IN (${mname1[@]}); 
        commit;             
    exit
!
        echo "**** Required Model Names from Deleted****" | tee -a /tmp/$MR.log    
    len=${#port_add_tab
[*]}
    while [ $i -lt $len ]
        do    
           mysql --user=${OPMDB_USR} --password=${OPMDB_PWD} ${DB_NAME} << ! | tee -a /tmp/$MR.log       
           set storage_engine=IPNODB;
           drop table if exists ${port_add_tab}; 
           exit
!
           echo "****Table: ${port_add_tab} is dropped****" | tee -a /tmp/$MR.log
       i=`expr $i + 1`
       done
fi
 
end=`date +%s%N`
dif=$(($end - $start))
 
echo "Execution time in nano seconds : $dif" | tee -a /tmp/$MR.log
echo "Done!! Script Executed successfully" | tee -a /tmp/$MR.log
echo "Please check the log in /tmp/$MR.log"

Can some one put some light on this to built my understanding more clear...

---------- Post updated at 04:39 PM ---------- Previous update was at 04:38 PM ----------

Script Output is:

***This script is used for DB Migration Clean-up for Static Tables removal***
DB_SYSTEM =MYSQL 
hiiiiiii
MY SQL Deleting the entry in static tables and pa_tab_info table
**** MY SQL Required Model Names  Deleted****
****Table: XYZ_100C is dropped****
Execution time in : 100
Done!! Script Executed successfully
Please check the log in /tmp/eml_msp131233.log
8

Problem was the two lines like this:

        !

Because they were not in column 1, all the lines from the <<! to the next line which did properly start with ! were treated as part of the Here Document. Thus most of your code did not execute (and that includes the "elif" line).

9

Thanks a lot methyl... Now I completely understood!:slight_smile:

Thanks a ton!!!
Ambar Agrawal

10

You need spaces around comparison operators - your second example is equivalent to just if [ sometext ] (which is always true).

(Unlike assignment, where you don't want spaces!)