Question

I’m stuck in this very easy problem (I hope it is for you).
I need to substitute several strings with special characters in a huge file.
I’m trying using sed and bash because I’m a linux user but I’ve only used sed for “standard” string so far.

These are the kind of strings that I’m trying to manipulate

(alpha[1],alpha[2]) and diff(A45(i,j),alpha[1])

and the substituting strings would be

(i,j) and dzA45(i,j)

I tried sed -i 's/(alpha[1],alpha[2])/(i,j)/g' $filetowork and
sed -i 's/\(alpha\[1\],alpha\[2\]\)/i,j/g' $filetowork without any success

The second option seems to work for the first kind of string but it doesn’t for the second one, why?

could you please help me? I took a look around stackoverflow old questions without any help, unfortunately 🙁

Answer 1

I just tried on the command line, but

echo "(alpha[1],alpha[2])" | sed 's/(alpha\[1\],alpha\[2\])/(i,j)/

worked for the first case. Please note that you should not escape ( or ), because that is how you activate groups.

For the second one

echo "diff(A45(i,j),alpha[1])" | sed 's/diff(A45(i,j),alpha\[1\])/dzA45(i,j)/'

worked for me. The same case, don’t escape brackets!