I am fetching the data from psql in the shell script and assign to the global variable but the global variable is not updating below i have tried:
#!/bin/bash
res_count=0
psql -h $db_host -U $db_user -d $db_name -At -c "select count(id) as dCount from abc" --no-password --field-separator ' ' | \
while read dCount ; do
res_count=$dCount
done;
echo $res_count
$res_count is not updating, it has still value 0, please correct me where i am wrong thanks
Your while loop executes in a subshell because it is executed as part of the pipeline. You can avoid it by using lastpipe or placing the psql command inside process substitution.
#/bin/bash
shopt -s lastpipe
...
Or
res_count=0
while read dCount ; do
res_count=$dCount
done < <(psql -h "$db_host" -U "$db_user" -d "$db_name" -At \
-c "select count(id) as dCount from abc"
--no-password --field-separator ' ')
echo "$res_count"
As a side note, quote your variables properly.
