Notes

cat a.sh (check the line in file existed or not)
#!/bin/bash


if grep -q "${1}" ${2}
then
# No error found in the log file
echo `date` " found string in ${2} "
else
# Errors found in the log file
echo `date` " Not found string ${1} in file "

fi


./c.sh (Calculate xxx days back from today's date)
write a number:
4
Today is Wed Feb 28 13:52:59 EST 2018
4 days back from today is Sat Feb 24 13:52:59 EST 2018
[nany@mdc-sec-devsas1 ~]$ cat c.sh
#!/bin/bash

echo " write a number: "
read num
Today=`date`
aday=$(date -d "-$num day")
echo " Today is ${Today} "
echo " ${num} days back from today is ${aday} "


Design Principles and Assumptions
1. Provide automation whenever possible.
2. Provide verification points throughout the ETL process.
3. Provide manual load tools for special occasions, such as data fix or data reload, utility to clean up: rollback, rangeload, weeklyload, singledataset load, removelogs, etc.
4. Apply the best practice for better performance.
§ Add partition
§ Using parallel loading
5. Provide alert, logging, metadata for best monitoring.

1. Function call with return value. Only 0-255 works correctly!!
2. b.sh don't need to be executable. It can be just read-only.


cat aa.sh
#!/bin/bash

source bb.sh

echo "This is the main script calling ......."

bb
rev=$?

echo "Return value in the caller: ${rev}"

[nany@mdc-sec-devsas1 ~]$ cat bb.sh
#!/bin/bash

bb()
{
i=256
echo "Inside function value i: $i"
return $i
}

[nany@mdc-sec-devsas1 ~]$ ./aa.sh
This is the main script calling .......
Inside function value i: 256
Return value in the caller: 0