Can anybody help me to understand the script and...

[Shahbaz_1]

Hi Friends,
I've a typical task, a shell script, may be written in AIX, need to convert to hp-ux.

following is the script,
----
Change script name to lower case
QUERY='echo $1 |tr "[A-Z]" "[a-z]".sql
#Create the body of SQL(OTXUP20.sql)
build ()
{
SQL='cat $YDEBTSQL/$QUERY'
cat $YDEBTSQL/insertCT.sql > $YDEBTSQL/OTXUP20.sql
if [ "$?" != "0" ]
then
exit 9
fi
echo "SQL" >> $YDEBTSQL/OTXUP20.sql
if ["$?" !="0"]
then
exit 9
fi
cat $YDEBTSQL/exit.sql >> YDEBTSQL/OTXUP20.sql
if ["$?" !="0"]
then
exit 9
fi
}
runit()
------
First I think need to understand, what exactly it is doing, then move to the next part...

Please ...

Thanks in Adv.

Regards
Shah

[Bill McNAMARA_1 · Accepted solution]

QUERY='echo $1 |tr "[A-Z]" "[a-z]".sql


>>> seems to be a missing quote at the end.
>>> I prefer to use
>>> QUERY=$('echo $1 |tr "[A-Z]" "[a-z]".sql)
>>> although both will work.
>>>
>>> this bit just tr(anslates) $1
>>> $1 being the first arg of the script
>>> to lowercase.
>>>
>>> ie:
>>> scriptname hostname user port
>>> $0 $1 $2 $3
>>>

#Create the body of SQL(OTXUP20.sql)
build ()
{
SQL='cat $YDEBTSQL/$QUERY'

>>> $YDEBTSQL is obviously a directory name
>>> $QUERY is the filename we just lowercased
>>> $SQL is now the content of that file.

cat $YDEBTSQL/insertCT.sql > $YDEBTSQL/OTXUP20.sql

>>> same as cp $YDEBTSQL/insertCT.sql $YDEBTSQL/OTXUP20.sql


if [ "$?" != "0" ]
then
exit 9
fi

>>> command error codes are returned to the
>>> shell and referenced by echo $?
>>> no error = return code 0
>>> here your application/script, will return
>>> an error 9 if it can't do the previous
>>> operation.


echo "SQL" >> $YDEBTSQL/OTXUP20.sql
>>>
>>> this will redirect the text SQL
>>> into a newline in the file OTXUP20.sql
>>> common mistake is to:
>>> echo "SQL" > $YDEBTSQL/OTXUP20.sql
>>> that just creates a file with text SQL
>>> and 'erases' previous content of the file.


if ["$?" !="0"]
then
exit 9
fi
cat $YDEBTSQL/exit.sql >> YDEBTSQL/OTXUP20.sql
if ["$?" !="0"]
then
exit 9
fi
}
runit()

runit()
is referencing a function defined somewhere else in this script or in a referenced script.

Later,
Bill

[T G Manikandan]

First it is changing the filename which is entered as argument, to lowercase.
Then,it is just doing a cat of insertCT.sql,$QUERY and exit.sql and storing it in a single file i.e.getting the contents of the three files and storing it in OTXUP20.sql.
In the meanwhile it is checking for the status to be successful.
The script exits if one of the steps where it is doing a cat and storing to OTXUP20.sql fails.


Thanks

Thanks

[Shahbaz_1]

Hi Bill & Manikandan,
Thanks Lot,
some times, we don't understand simple things, may be because of lack of patience.
You people are very good. great,,

Now I understand the script, but the following line,

echo "SQL" >> $YDEBTSQL/OTXUP20.sql

to me it is just appending the word "SQL" to $YDEBTSQL/OTXUP20.sql file.
or is it the script writer trying to store the content of SQL file to the above file?

...

Regards
Shah

[T G Manikandan]

shah,

how about
echo "$SQL" >>/...


THanks

[Bill McNAMARA_1]

SQL='cat $YDEBTSQL/$QUERY'

SQL variable now contains the content of the Query file.


cat $YDEBTSQL/insertCT.sql > $YDEBTSQL/OTXUP20.sql

This is the same as a copy

echo "SQL" >> $YDEBTSQL/OTXUP20.sql

This echos the text
SQL
in a new last line of $YDEBTSQL/OTXUP20.sql
It possibly should be

echo "$SQL" >> $YDEBTSQL/OTXUP20.sql

in order that the SQL variable is referenced, but then
cat $YDEBTSQL/$QUERY >> $YDEBTSQL/OTXUP20.sql

does exactly the same thing..

possibly you want to have lots of tests done, and exist codes everywhere..

Later,
Bill