UNIX for Dummies Questions & Answers

Hello,

In manpage magic(5)
"
The “B” flag compacts whitespace in the target, which must contain at least one whitespace character. If the magic has n consecutive blanks, the target needs at least n consecutive blanks to match. The “b” flag treats every blank in the target as an optional blank. " is writing for string/B type.
I create a magic.mime with a line

"0 string/B melemen\ 123\ \ abc filedetected"


and first line of myfile is "melemen 123 abc" //Note: there are at least two blanks between 123 and abc but not appear here.

when my data in magic file is like that "melemen\ 123\ abc" it prints "filedetected" but when there are two blank between
123 and abc like "123\ \ abc" it does not work.However according to explanation it sohuld be work. I do not understand where I am wrong.


My second problem is about ampersand
what does "&" mean when it is used at the begining of offsets like

0 string ...
>4 string...
>>&0 string....



There is not enough information about magic operators on the internet so sometimes I have difficulty understanding functionality of operators.

magic only works when the OS is invoking a new file via exec().
It is used to tell the system what interpreter to run or how to load the file into memory.

Some systems extend this (Solaris is one) to be able to identify all kinds of file types -- using the file command -- which do not really fit into the above statement.

1. what are you trying to do?
2. what OS (each OS has different ideas about magic)?

I am trying to implement a program in erlang which detects file types.I am using unix's database magic.mime and its syntax.My system is ubuntu.

You have two consecutive blanks...so do you have 2 consecutive /B to match them as per the manpage.

I don't understand what do you mean with 2 consecutive /B. I tried string/BB and
string/B/B and some other combinations but no result.