Using shell variable in psql command

Question

I need some help into sending a shell variable to a psql -c query inside a .sh:

#!/bin/sh

    timeStamp=`date +%s`
    timeStampLast24H= expr $timeStamp - 86400

    psql -U postgres -c "COPY (SELECT atribute FROM table WHERE ts>$timeStampLast24H) TO stdout DELIMITER ';' CSV HEADER; > (...)"

I'm doing this to get only rows from the last day because the person who created the database used rectimestamp as an integer, and normal functions from postgres won't work ( now()-interval 'Given_Period' , for example).

Changing "$timeStampLast24H" by something that makes postgres understand an integer that corresponds exactly to the timestamp in from the last 24h is also ok for me. If I use an exact timestamp in its place, the query works well.

Thanks.

Answer 1

This assignment

timeStampLast24H= expr $timeStamp - 86400

is incorrect.

Notice how it differs from this assignment?

timeStamp=`date +%s`

You added a space after the = and left out the backticks or $() wrapping.

Fix those problems and your issue will likely go away. As it is you are putting no value into your query.