From: Tom Lane <tgl@sss.pgh.pa.us>
To: "David G. Johnston" <david.g.johnston@gmail.com>
cc: Murthy Nunna <mnunna@fnal.gov>,
        Pgsql-admin <pgsql-admin@lists.postgresql.org>
Subject: Re: Having trouble passing a shell variable to a query from psql
 command line
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Comments: In-reply-to "David G. Johnston" <david.g.johnston@gmail.com>
	message dated "Fri, 29 Aug 2025 10:58:03 -0700"
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Date: Fri, 29 Aug 2025 14:16:21 -0400
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"David G. Johnston" <david.g.johnston@gmail.com> writes:
> On Fri, Aug 29, 2025 at 10:52=E2=80=AFAM Murthy Nunna <mnunna@fnal.gov> =
wrote:
>> psql -d mydb -t -A -c "SELECT relkind FROM pg_class WHERE relname =3D
>> :'SHELL_VAR' ;" -v SHELL_VAR=3D"$SHELL_VAR"
>> =

>> ERROR:  syntax error at or near ":"
>> =

>> LINE 1: SELECT relkind FROM pg_class WHERE relname =3D :'SHELL_VAR' ;

> I provide the documentation.  Under psql -c:
> "command must be either a command string that is completely parsable by =
the
> server (i.e., it contains no psql-specific features)"

Yeah.  The argument of a -c switch is just sent to the server as-is.

However, you don't need a script file to fix this.  You can do
something like

echo "SELECT relkind FROM pg_class WHERE relname =3D :'SHELL_VAR' ;" | psq=
l -d mydb -t -A -v SHELL_VAR=3D"$SHELL_VAR"

			regards, tom lane