How to iterate a list of numbers through sed command in bash-CodePudding

I want to modify a specific line in my code

program main
...
seed=k rank
...
end

and increment k by intervals of m(=96, in my example). So my implementation of the same in shell should look something like

for k in {1..961..96};
do sed -i "s/{seed=k rank}/{seed=k 96 rank}/g" main.f90;
#run the program
sleep 15m;
done

but this changes the string seed=1 rank to seed=1 96 rank instead of writing 97 rank and would not proceed on the next iteration.

(Bash script using sed with variables in a for loop? is what I could find)

I've searched for the use of sed through a bash loop but couldn't find or figure out the command specific to my purpose.

CodePudding user response：

You shouldn't do the replacement in place. After the first iteration, the file won't have k in it any more, since k will have been replace. You should read from a template file and write to a different file that will be executed.

You need to use $k in the replacement string to get the value of the shell variable.

And you shouldn't have {} in the sed pattern or replacement.

for k in {1..961..96};
    do sed "s/seed=k rank/seed=$k rank/g" template.f90 > main.f90;
    #run the program
    sleep 15m;
done

Although I wonder why you don't just change the program so that it gets the value of k from a command-line argument or standard input. Then you won't have to modify the program for each run.

CodePudding user response：

ok, this worked:

for k in {1..961..96}; 
do m=$k; n=$(($k 96)); 
sed -i "s/seed=$m rank/seed=$n rank/g" main.f90 ;
#run main program
sleep 15m 
done