psql shell command execution with \!

Question

Is there any way to capture shell output (in a psql variable) and/or the exit code of running a shell command from inside psql using \!? The documentation provides no details.

Answer 1

Using \! with \o..

You can combine the two like this,

• \! echo "SELECT 1;" > bar (runs the command echo "SELECT 1;" redirects output of SELECT 1; to bar)
• \o bar (runs the commands in bar)

Answer 2

Seems to be impossible for \!,

but one can set a variable from external command output,

testdb=> \set content `cat my_file.txt`

and then using this var in sql expression like this:

testdb=> INSERT INTO my_table VALUES (:'content');