Please help with function

[SimonTempler]

Here's an excerpt of the code. Please somebody explain this line (MIG_INFO=`grep $1 /u02/app/psoft/fs800/$BASE_ENV_LOWER/migrations/todo/$BATCH`)...I just don't see where the $1 variable is defined anywhere in the function. The script is called M_FQA8.

Thanks for your help.

###################################################################
# Function: update_program #
# Description: This function will be used to update the #
# S_MIG_BATCH_PRG table in the source environment, #
# with the status of the migration. The SQL is #
# dynamically created, using the input parameter: #
# $1 = program name, with extenstion #
###################################################################
function update_program
{
# Change 6 - Begin - added these lines
MIG_INFO=`grep $1 /u02/app/psoft/fs800/$BASE_ENV_LOWER/migrations/todo/$BATCH`
FILE_DESCR=`echo $MIG_INFO | awk -F: '{print $1}'`
OBJECT_INFO=`grep "$FILE_DESCR" objects.txt`
OBJECTTYPE=`echo $OBJECT_INFO | awk '{print $1}'`
OBJECTID1=`echo $OBJECT_INFO | awk '{print $2}'`
OBJECTID2=`echo $OBJECT_INFO | awk '{print $3}'`
# Change 6 - End

if [ -f mig.sql ]
then
rm mig.sql
fi

SHORT_NAME=`echo $1 | awk -F. '{print $1}'`
EXT=".`echo $1 | awk -F. '{print $2}'`"

echo "Update PS_S_MIG_BATCH_PRG " >>mig.sql
echo " set S_MIG_COPYDONE='$DONE_FLG', " >>mig.sql
echo " S_MIG_MESSAGE='$MIG_MSG'" >>mig.sql
echo "where PROJECTNAME='$PROJ_NAME'" >>mig.sql
echo " and S_TGT_ENVIRONMENT='$T_ENV'" >>mig.sql

# Change 6 - Begin - added the if/then/else, these are the old lines
#echo " and OBJECTVALUE1='$SHORT_NAME'" >>mig.sql
#echo " and OBJECTVALUE2='$EXT';" >>mig.sql
if [ "$OBJECTID2" = 0 ]
then
SHORT_NAME=`echo $1 | awk '{print $1}'`
echo " and OBJECTVALUE1='$SHORT_NAME';" >>mig.sql
else
echo " and OBJECTVALUE1='$SHORT_NAME'" >>mig.sql
echo " and OBJECTVALUE2='$EXT';" >>mig.sql
fi
# Change 6 - End

echo " " >>mig.sql
echo "commit;" >>mig.sql
echo " " >> mig.sql
echo "exit" >> mig.sql

echo " " >>mig.log
echo "Update SQL:" >>mig.log
cat mig.sql >> mig.log
sqlplus -s $SQLUSER/$SQLPASS@$BASE_ENV @mig.sql >> mig.log

if [ "$DONE_FLG" = "Y" ]
then
update_history $1
fi
}

 

[lgarner]

$1 is the first command-line parameter.

If you type "myprogram test", then $1 = "test"

 

[SimonTempler]

Thanks!....is $1 the same outside of the function ?. Reason is, after the above function, there's another function call $1 and $2 and i'm confused as to if it's the same value.

See code below...

###################################################################
# Function: Migrate_File #
# Description: This function will be used to do the actual moving #
# or copying of the files. #
# There are two input parameters to this function: #
# $1 = full path of source file #
# $2 = full path of target file #
###################################################################

function migrate_file
{
# Change 7 - Begin - Simplified this function by using SCP, removed large amount of code.
# copy the file to the target
$SCP $1 $TARGET_IP:$2 >> mig.log 2>&1

# If the copy failed, log it and set flags to fail
if (( $? != 0 ))
then
echo " " | tee -a mig.log
echo "ERROR: Error in transfer of $1 to $TARGET_IP:$2." | tee -a mig.log
MIG_MSG="Source to target copy failed."
DONE_FLG="N"
STATUS=1
else # copy was successful
echo "Successful transfer of $1 to $TARGET_IP:$2." | tee -a mig.log

# change permissions on the file that just got copied
$SSH $TARGET_IP $CHMOD 755 $2 >> mig.log 2>&1

# If CHMOD failed, log it and set flags to fail
if (( $? != 0 ))
then
echo " " | tee -a mig.log
echo "ERROR: Error in changing permissions of $TARGET_IP:$2." | tee -a mig.log
MIG_MSG="CHMOD of target failed."
DONE_FLG="N"
STATUS=1
else # CHMOD was successful
echo " " | tee -a mig.log
echo "Successful CHMOD of $TARGET_IP:$2." | tee -a mig.log
MIG_MSG="Successful."
DONE_FLG="Y"
STATUS=0
fi
fi
# Change 7 - End
}

 

[lgarner]

Sorry, I had the wrong train of thought. Yes, the parameters work the same way with functions.

In this case, the function would be called something like:

migrate_file /home/myself/sourcefile /var/tmp/destfile

The parameters might not be defined anywhere. I could see how this script would simply pass the command-line arguments that I mentioned before, so the function might be called like this:

migrate_file $1 $2

where $1 and $2 are the first and second command-line arguments.

 

[SimonTempler]

The question is what is $1 and $2 in Migrate_file function. I can understand if $1 is coming from the function update_program but what is $2 ?

 

[lgarner]

They are defined when migrate_file is called. It's not being called by update_program, so it must be called somewhere else.

You havent included any function calls for update_program or migrate_file, only the functions themselves. They must be called somewhere else in the script, and the $1 and $2 would be defined there.

 

[chipperMDW]

function print_my_parameters
{
    echo $1 $2 $3
}

print_my_parameters one two three
print_my_parameters hello world goodbye
print_my_parameters do you understand
print_my_parameters how parameters work?

Output

one two three
hello world goodbye
do you understand
how parameters work?

 

[SimonTempler]

@lgarner i saw where the function is later called.

Thanks for all your help.

@ChipperMDW, thanks!. Now i understand how parameter works.