s/\~\//\$HOME\//g - There's possibly a nicer way to make sure tilde expansion is done in the right places, but this works just as well and doesn't require extra thinking when I'm half asleep :P Added (^|:) to start, and ($|:) to end of all tests to make sure we're matching a full path. Also test for (and append if not there) a ':' at the end of $MANPATH; otherwise Linux systems tend to forget how to search system paths.