Try MSAR.

In file:

1:2  
-p 1 -t 2 3 
1 2
[download]

Map file:

1    arg1
2    arg2
3    arg3
[download]

Output:

{C} > msar in.txt map.txt
Reading mappings from file:  map.txt
----------------------------
arg1:arg2
-p arg1 -t arg2 arg3
arg1 arg2
----------------------------
Mapped 7 entries.
[download]

You can review the coding in MSAR.pl, but I think you'll be interested in the regex:

($_ =~ s/$replace/$map{$replace}/gi)
[download]