Mass Load of Keyboard/Text mappings in Mavericks
The settings are stored in ~/Library/Preferences/.GlobalPreferences.plist in the NSUserDictionaryReplacementItems array in 10.9 and in the NSUserReplacementItems array in 10.8 and earlier. The format of the array has not changed, so the commands below should work in 10.8 and earlier versions of OS X if you replace NSUserDictionaryReplacementItems with NSUserReplacementItems.

Print the current settings:

defaults read -g NSUserDictionaryReplacementItems


Add one setting:

defaults write -g NSUserDictionaryReplacementItems -array-add '{on=1;replace=cmd;with="⌘";}'


Replace all settings:

defaults write -g NSUserDictionaryReplacementItems '(
{on=1;replace=cmd;with="⌘";},
{on=1;replace=opt;with="⌥";}
)'


Print the current settings as XML:

defaults read -g NSUserDictionaryReplacementItems | plutil -convert xml1 - -o -


Replace all settings:

amp() { local x=${1//&amp;/&amp;amp; }; x=${x//&lt;/&amp;lt; }; printf %s "${x//&gt;/&amp;gt; }"; }
out='&lt;array&gt;'
while IFS= read -r l; do
  out+="&lt;dict&gt;&lt;key&gt;on&lt;/key&gt;&lt;integer&gt;1&lt;/integer&gt;&lt;key&gt;replace&lt;/key&gt;&lt;string&gt;$(amp "${l%% *}")&lt;/string&gt;&lt;key&gt;with&lt;/key&gt;&lt;string&gt;$(amp "${l#* }")&lt;/string&gt;&lt;/dict&gt;"
done &lt;&lt;&lt; 'cmd ⌘
opt ⌥'
defaults write -g NSUserDictionaryReplacementItems "$out&lt;/array&gt;"


You can apply changes made with defaults by quitting and reopening applications.