Or a variant using colon-terminated lines rather than colon-separated fields, allowing the uniqueness code itself to be very straightforward: 
MYPATH=$(echo -n "$PATH"|perl -072 -lne 'print unless $s{$_}++')

[download]
(octal 072 is ":", the colon character)

Because this is interpreting the entries in $PATH as colon-terminated rather than colon-separated, though, this will tack on an unwanted colon at the end.

So the full solution wouldn't be as pretty. You'd need something like: 

MYPATH=$(echo -n "$PATH"|perl -072 -lne 'print unless $s{$_}++')
MYPATH="${MYPATH%:}"

[download]

In reply to Re^2: Perl one-liner to remove duplicate entries from PATH by sfink
in thread Perl one-liner to remove duplicate entries from PATH by eyepopslikeamosquito

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