Changes between Version 62 and Version 63 of FAQ

Timestamp:

Mar 27, 2009, 1:48:59 AM (16 years ago)

Author:

blb@…

Comment:

Add info on using force option

FAQ

@@ -188 +188 @@
 Using separate ports for these modules (like py25-readline) avoids the need to completely rebuild the base port, and can be used as a dependency, but ends up having other issues.  One is that these modules are installed using the standard distutils method for python, which causes them to be installed in a different location than where they would be when installed normally (see ticket #12369).  The other is that many python developers have expectations when they install python, and installing python24 or python25 simply does not match that.
 
+=== When should I use the force option (-f) === #whentoforce
+
+Use of the force option (-f) is rarely necessary, but some suggestions in the past have recommended its use quite frequently.  One of the few useful applications of it is in forcing a reinstall of an already-installed port to add a new variant, for example
+{{{
+sudo port -fn upgrade mysql5 +server
+}}}
+will install a new version of the mysql5 port with the current variants plus +server.  Note the use of the -n (don't follow dependencies) option, which is important in this case (otherwise ports depended on by mysql5 will be upgraded as well even when it isn't needed).
+
+One of the other times -f is needed is when you run into a stray file in your MacPorts prefix, not owned by a port, but blocks the install of one.  This is seen with an error message from port similar to
+{{{
+Error: Activating some-port @1.0_0 failed: Image error: /opt/local/path/to/stray/file already exists and does not belong to a registered port.  Unable to activate port some-port.
+}}}
+Unless you know the source of that file and that you need to keep it, this is a good use of force.  However, don't use it with '''install''' but with activate:
+{{{
+sudo port -f activate some-port
+}}}
+Outside of `-fn upgrade` and `-f activate` force can be extremely dangerous, and should be avoided unless you know precisely how port is going to act.
+
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