General Search

Ubuntu has mlocate but on other systems you will need to use find (which also will work on Ubuntu too),

find [folder] -name [filename] -print # find a file
find [folder] -size +51024 -print     # where 51024 is in Kilobytes which is approximately 5MB

Search Inside of Multiple Files

Also works in Solaris and Unix in general. Make sure to add trailing slash to [folder]. For example, "/opt/confluence/"

find [folder] -type f | xargs -I{} grep -li "text" {}

find [folder] -type f                  # search the specified folder for all files, returns full path of each file
    | xargs -I{} grep -li "[text]" {} # piped into xargs to grep for all files containing specified text ignoring case

Replace

Search and Replace Single File using sed

See dedicated section on sed.

Search & Replace Inside of Multiple Files Across Folders

The key is using xargs. Used Perl this here bue can easily be replaced with sed,

find [folder] -type f | xargs -I{} grep -li "text" {} | xargs perl -pi -e 's/[text_to_search_for]/[text_to_search_for]/g'

find [folder] -type f                 # search the specified folder for all files, returns full path of each file
    | xargs -I{} grep -li "[text]" {} # piped into xargs to grep for all files containing specified text ignoring case
    | xargs perl -pi -e 's/[text_to_search_for]/[text_to_replace_with]/g' # pipe list of files and using perl search and replace with specified text