shell - How to replace a character in a specific position in a flat file

Question

I am having a flat file with huge data, there are 924 characters in one line, in solaris server. Now i want to goto the specific position in each line - say 234, and check if it has "R" as the character, if it has "R" then replace it with "x". How can i write a shell script with these conditions?

question from:https://stackoverflow.com/questions/65849989/how-to-replace-a-character-in-a-specific-position-in-a-flat-file

Answer 1

I don't have a Solaris system to test on: this should work:

sed -E 's/^(.{233})R/1x/' file

That does not modify the file. To save a backup copy and modify the file in-place:

sed -i .bak -E '...' file

Use -i '' if you don't want a backup.

Reiterating: I don't have Solaris, and these option may not work with the Solaris sed.