c# - How to replace > 1 tokens on a string? -

i have list of tokens

 [@date]  [@time]  [@filename]  ... etc 

that dispersed on large file. can parse file , replace them regex.replace when there's 1 token on line. problem arises when there's 2 tokens on 1 line
example:

[@date] [@time] 

what thought doing using string.split " " delimiter, , iterate through result checking if there tokens.

but see 2 problems approach, file rather large , impact performance. second problem file outputted sql file , i'd retain white space looks.

is there more elegant solution problem? or case of premature optimization?

one thing can instead of replacing patterns line line, replace them in whole file:

string filecontent = file.readalltext(path); filecontent = regex.replace(filecontent, pattern1, replacement1); ... filecontent = regex.replace(filecontent, patternn, replacementn);