Remove gratuitous references to postmaster program

"postgres" has long been officially preferred over "postmaster" as the
name of the program to invoke to run the server.  Some example scripts
and code comments still used the latter.  Change those.

Discussion: https://www.postgresql.org/message-id/flat/ece84b69-8f94-8b88-925f-64207cb3a2f0@enterprisedb.com

contrib/start-scripts/freebsd

@@ -16,7 +16,7 @@ prefix=/usr/local/pgsql
 # Data directory
 PGDATA="/usr/local/pgsql/data"
 
-# Who to run the postmaster as, usually "postgres".  (NOT "root")
+# Who to run postgres as, usually "postgres".  (NOT "root")
 PGUSER=postgres
 
 # Where to keep a log file
@@ -27,14 +27,14 @@ PGLOG="$PGDATA/serverlog"
 # The path that is to be used for the script
 PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
 
-# What to use to start up the postmaster.  (If you want the script to wait
+# What to use to start up postgres.  (If you want the script to wait
 # until the server has started, you could use "pg_ctl start" here.)
-DAEMON="$prefix/bin/postmaster"
+DAEMON="$prefix/bin/postgres"
 
-# What to use to shut down the postmaster
+# What to use to shut down postgres
 PGCTL="$prefix/bin/pg_ctl"
 
-# Only start if we can find the postmaster.
+# Only start if we can find postgres.
 test -x $DAEMON ||
 {
 	echo "$DAEMON not found"

contrib/start-scripts/linux

@@ -34,7 +34,7 @@ prefix=/usr/local/pgsql
 # Data directory
 PGDATA="/usr/local/pgsql/data"
 
-# Who to run the postmaster as, usually "postgres".  (NOT "root")
+# Who to run postgres as, usually "postgres".  (NOT "root")
 PGUSER=postgres
 
 # Where to keep a log file
@@ -59,16 +59,16 @@ PGLOG="$PGDATA/serverlog"
 # The path that is to be used for the script
 PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
 
-# What to use to start up the postmaster.  (If you want the script to wait
+# What to use to start up postgres.  (If you want the script to wait
 # until the server has started, you could use "pg_ctl start" here.)
-DAEMON="$prefix/bin/postmaster"
+DAEMON="$prefix/bin/postgres"
 
-# What to use to shut down the postmaster
+# What to use to shut down postgres
 PGCTL="$prefix/bin/pg_ctl"
 
 set -e
 
-# Only start if we can find the postmaster.
+# Only start if we can find postgres.
 test -x $DAEMON ||
 {
 	echo "$DAEMON not found"

src/port/path.c

@@ -651,7 +651,7 @@ dir_strcmp(const char *s1, const char *s2)
  * For example:
  *		target_path  = '/usr/local/share/postgresql'
  *		bin_path	 = '/usr/local/bin'
- *		my_exec_path = '/opt/pgsql/bin/postmaster'
+ *		my_exec_path = '/opt/pgsql/bin/postgres'
  * Given these inputs, the common prefix is '/usr/local/', the tail of
  * bin_path is 'bin' which does match the last directory component of
  * my_exec_path, so we would return '/opt/pgsql/share/postgresql'