How to replace a string in file in Linux

https://www.cyberciti.biz/faq/how-to-use-sed-to-find-and-replace-text-in-files-in-linux-unix-shell/

sudo sed   's/efs/fileshare/g' /etc/fstab   //Replace content and its temporary

sudo sed   's+/efs+/fileshare+g' /etc/fstab  // Change Delimiter

sudo sed  -i 's+/efs+/fileshare+g' /etc/fstab //-i save changes to file/stream

sudo sed  -e '/fs-face524e/s/fileshare/helloooo/' /etc/fstab //Replace only if lines contain specific string "fs-face524e"