shell - Replacing text with sed -

My file has a line like this

  integer, parameter :: L = 2! The size of the system  

can be any integer number where the number 2 is to use this code sed and with the other The value of the number is to change.

I tried:

  $ L = 5 $ i '/ l = / c \ integer, parameter :: l = $ l! System size 'sed moduleselfcons.f90  

But in my modified file I have

  integer, parameter :: L = $! System size  

no more:

  integer, parameter :: L = 5! System size  

What's the problem?

You should use double quotation marks ( ") of single quotes Instead ( ').

But I think you can shorten the expression:

  L = 5 sed "s / l = [0-9] * / l = $ l / "file  

If it is yours add -i flag to the desired output in-place editing. < / P>