don't understand the basics of insert/part

[newbie]

I want to insert 7 after 123456 but it doesn't work it seems so basic to do  :blink:

>> a: "123456.txt"
== "123456.txt"
>> insert/part a "7" 7
== "123456.txt"
>> a
== "7123456.txt"
>>

[CarlRead]

INSERT always works in the start of a series.  Using it with SKIP will do what you want, though...

>> a: "123456.txt"
== "123456.txt"
>> insert skip a 6 "7"
== ".txt"
>> a
== "1234567.txt"