How to escape quotes in a docker postgres command - postgresql

Question

I have the following command that I'm running (renamed some variables):
docker exec docker_name sh -c 'psql dbname -U joeadmin -c "update table set field='really_longstringwithabunf3493829#########=';"'
When I run this, it will throw the following error:
ERROR: syntax error at or near ";"
LINE 1: ...longstringwithabunf3493829#########=;
^
How can I escape or retain the single quotes so this will work. Also, if this is just a horrible way of approaching this, I'm open to other suggestions. The use case is making changes to a db on a docker container before exporting data out of it.

Answer 1

Working with strings can be a bit ugly at times with Docker. In your case, I would suggest using double-quotes first, then escape inner double-quotes with \:
docker exec docker_name sh -c "psql dbname -U joeadmin -c \"update table set field='really_longstringwithabunf3493829#########=';\""
A cleaner option would be to create an environment variable:
STR="really_longstringwithabunf3493829#########="
docker exec docker_name sh -c "psql dbname -U joeadmin -c \"update table set field='${STR}';\""
Bear in mind that string interpolation happens in the host OS, not in the container (unless you escape the dollar-sign with \${STR}
Still cleaner would just be to create a file and then copy it into the container:
echo "update table set field='really_longstringwithabunf3493829#########=';" > ~/myfile.txt
docker cp ~/myfile.txt docker_name:/tmp
docker exec docker_name sh -c "psql dbname -U joeadmin -f /tmp/myfile.txt"