From c40b2d59e0dbac5a5215c9e1e9f05b22fcae6f13 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 14 Feb 2014 12:54:46 -0500
Subject: [PATCH] Suggest shell here-documents instead of psql -c for multiple
commands.
The documentation suggested using "echo | psql", but not the often-superior
alternative of a here-document. Also, be more direct about suggesting
that people avoid -c for multiple commands. Per discussion.
---
doc/src/sgml/ref/psql-ref.sgml | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml
index 5ae48b81a18..3344348f048 100644
--- a/doc/src/sgml/ref/psql-ref.sgml
+++ b/doc/src/sgml/ref/psql-ref.sgml
@@ -83,14 +83,15 @@ PostgreSQL documentation
(<filename>psqlrc</filename> and <filename>~/.psqlrc</filename>) are
ignored with this option.
</para>
- <para><replaceable class="parameter">command</replaceable> must be either
+ <para>
+ <replaceable class="parameter">command</replaceable> must be either
a command string that is completely parsable by the server (i.e.,
it contains no <application>psql</application>-specific features),
or a single backslash command. Thus you cannot mix
<acronym>SQL</acronym> and <application>psql</application>
meta-commands with this option. To achieve that, you could
- pipe the string into <application>psql</application>, like
- this: <literal>echo '\x \\ SELECT * FROM foo;' | psql</literal>.
+ pipe the string into <application>psql</application>, for example:
+ <literal>echo '\x \\ SELECT * FROM foo;' | psql</literal>.
(<literal>\\</> is the separator meta-command.)
</para>
<para>
@@ -102,6 +103,19 @@ PostgreSQL documentation
<application>psql</application>'s standard input. Also, only
the result of the last SQL command is returned.
</para>
+ <para>
+ Because of these legacy behaviors, putting more than one command in
+ the <option>-c</option> string often has unexpected results. It's
+ better to feed multiple commands to <application>psql</application>'s
+ standard input, either using <application>echo</application> as
+ illustrated above, or via a shell here-document, for example:
+<programlisting>
+psql <<EOF
+\x
+SELECT * FROM foo;
+EOF
+</programlisting>
+ </para>
</listitem>
</varlistentry>
--
GitLab