Question

This is my below shell script which I am using to query the hive tables and I saved this file as test4.sh

#!/bin/bash

DATE_YEST_FORMAT1=`perl -e 'use POSIX qw(strftime); print strftime "%Y-%m-%d",localtime(time()- 3600*96);'`
echo $DATE_YEST_FORMAT1

QUERY1=`hive -e "
set mapred.job.queue.name=hdmi-technology;
SELECT split(ckey, '\\|') AS t1
                    ,created_time
                FROM (
                    SELECT CONCAT (
                            buyer_id
                            ,'|'
                            ,item_id
                            ) AS ckey
                        ,created_time
                    FROM dw_checkout_trans
                    WHERE to_date(from_unixtime(cast(UNIX_TIMESTAMP(created_time) AS BIGINT))) = '$DATE_YEST_FORMAT1' distribute BY ckey sort BY ckey
                        ,created_time DESC
                    ) a
                WHERE rank(ckey) < 1;"`

Problem Statement:-

I am running the above shell script as-

bash -x test4.sh

If you see this line in the above hive sql query:

**SELECT split(ckey, '\\|') AS t1**.  

Do I need to escape slash sign to make it to work in shell script?

Answer 1

Inside backticks and double quotes, you basically need to double your backslashes, yes. If a backslash is not a known escape sequence, it will be preserved, though.

bash$ echo "foo\bar"
foo\bar

bash$ echo "foo\\bar"
foo\bar

bash$ echo "split(ckey, '\\|')"
split(ckey, '\|')

So if you want hive to see a double backslash there, you will need to put four backslashes in the Bash script.

See further e.g. http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_03_03.html