Question

I tried to use the query outside of the database. That is, without login to data base
I want to get the result. I found the option (-c). Using that option we can execute the query from outside the data base:

test:~$ psql  -U sat -c "select * from test.details";

It gives the output. I want to use that query for a crontab entry. So I have tried to store the output in a file:

 test:~$ psql  -U sat -c "select * from test.details \g sat";

Produced an error:

ERROR:  syntax error at or near "\"
LINE 1: select * from test.details \g sat

How to do that?

Answer 1

This is not a slash, but a backslash .
Backslash is an escape character in PostgreSQL string literals, therefore you have to double it to get a single backslash into the actual data.
If you want to store the result of a query into a file from the command line you have to use the -o command line option,so your query will become :

psql  -o filename -U sathishkumar -c "select * from hospital_management.patient_details";