How to replace certain strings?

Question

bash

There is this line:

# secureboot
service setlockstate /sbin/setlockstate
   class core
   oneshot
   seclabel u:r:vold:s0

This block in the code field must be replaced with # secureboot off. How to do it?

Answer 1

For starters, this is a comment, why change it?
Second, use, for example, sed
sed -i 's/чтоменять/на что менять/g' filename
PS To replace the entire block, you can specify a null delimiter and write a regexp that captures the entire block, for example

sed -zi 's/# secureboot\nservice.*\n.*class core\n.*oneshot\n.*seclabel.*/# secureboot off/g' FILENAME

Answer 2

sed 's/# secureboot/# secureboot off' < infile > outfile