Run PSQL command from bash script

Question

I would like to know how to run \du within a script, and output that to a file.

Something like the following:

# some_script.sh
psql <database connection> & \du > output_of_du.txt

I can find information about running .sql files via psql, but I can't find information about running psql commands themselves.

I found the following whilst searching:

• https://stackoverflow.com/questions/35347368/unable-to-run-psql-command-from-within-a-bash-script - about running SQL not a PSQL command
• https://stackoverflow.com/questions/54619776/cannot-get-psql-command-to-run-in-bash-script - seems to be about running a .sql script

But they're not what I'm after.

Answer 1

You can use the -c flag and combine it with -L to gather the output:

psql <database connection> -c \du -L output_of_du.txt

See psql-tip number 1 (https://psql-tips.org/psql_tips_all.html#tip001) and psql-tip number 26 (https://psql-tips.org/psql_tips_all.html#tip026)