Fixing Mac OS X Lion's SSH UTF-8 Issues

After switching from Mac OS X v. 10.6 (Snow Leopard) to OS X v. 10.7 (Lion), I began experiencing some weird locale-related problems when using OS X as an SSH client. The issues I experienced include, amongst others:

• Having the terminal complain about invalid locale settings:

$ locale
locale: Cannot set LC_CTYPE to default locale: No such file or directory
locale: Cannot set LC_ALL to default locale: No such file or directory 
LANG=en_US.UTF-8
LANGUAGE=en_US:en
LC_CTYPE=UTF-8
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8" 
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8" 
LC_TELEPHONE="en_US.UTF-8" 
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

• Being unable to correctly type some characters (such as accented characters).
• Having programs that tunnel their traffic over SSH, such as Subversion, complain about invalid locale settings during their operations:

$ svn co svn+ssh://user@repository/path
svnserve: warning: cannot set LC_CTYPE locale
svnserve: warning: environment variable LC_CTYPE is UTF-8
svnserve: warning: please check that your locale name is correct
svnserve: warning: cannot set LC_CTYPE locale
svnserve: warning: environment variable LC_CTYPE is UTF-8
svnserve: warning: please check that your locale name is correct


In fact, if you look for example at the output of the locale command seen previously, you can see how the LC_CTYPE variable is set UTF-8 while all other LC_* variables (excluding the empty LC_ALL), are set to en_US.UTF-8 (which are correct according to that server settings).

What is the SSH client shipped with Lion doing? Apparently sending incorrect values to the server. It's not just a nuisance having to fix them after logging in, provided you're able to do so: this behaviour is breaking other programs tunnelling their traffic over SSH, such as Subversion, that aren't establishing an interactive SSH tunnel for the user.

Fortunately, the fix is quick: just tell the SSH client not to send any LC_* variable:

• Open the SSH client configuration file (/etc/ssh_config).
• Comment out the line that instructs the SSH client to send those variables (SendEnv LANG LC_*) from the general host configuration section (Host *). You should end up with the following fragment:

Host *

# SendEnv LANG LC_*

The configuration change will be immediately applied to any SSH session opened from now on.

Hope this helps.