regarding const variables/structures

Nicholas Mc Guire der.herr at hofr.at
Thu Sep 13 02:07:10 EDT 2018


On Thu, Sep 13, 2018 at 09:12:32AM +0530, inventsekar wrote:
> >>> A brute force grep in the kernel shows that there are 130493 " const "
> in there
> Hi Hofrat,
> 1. may i know the command to do this above grep please..

$ grep -cre " const " * | more

will give you the " const " count per file - and then put a shell loop around it

$ SUM=0 ; for N in `grep -cre " const " * | cut -f 2 -d ":" ` ; do let SUM=$SUM+$N ; done ; echo $SUM

...as noted "brute force"

> 2. (and the opposite) may i know the command to grep other type of
> variables/structures

well if you want to know how to do that then you do need to look at basics
if regular expressions are not clear then you might want to look at
those first. And grep really is not the right tool to search for specific
structures and their use use something like cscope.

Try to focus on doing work you understand including the tools and processes
around it - if you just are looking for a fast way of getting X patches
into the kernel you are wasting your time. What the work from Bhumika Goyal
shows is that its not about the complexity of the change but about the 
systematic approach based on using understanding a problem class, translating
it to an abstract representation amenable to tools (coccinelle in this case)
and documenting her understanding in the commit messages to each patch. 

thx!
hofrat 



More information about the Kernelnewbies mailing list