How To Use Look Command.
The look command in Linux shows the lines beginning with a given string. This command also uses binary search if the file is sorted. If file is not specified, the file /usr/share/dict/words is used. And then only the alphanumeric characters are compared and the case of alphabetic characters is ignored.
-[string]: This option is used to search for the given string in a specified file.
-f : This option is used to ignore case of alphabetic character.
-t: This option is used to specify a string termination character, i.e., only the characters in string up to and including the first occurrence of character are compared.
-d: This option is used to compare only alphanumeric characters.
-bd, -bf: This option uses binary search on the given word list. If you are ignoring case with -f or ignoring non-alphanumeric characters with -d, the file must be sorted in the same way.
-h: This option is used to show the help message and exit.
-V: This option is used to show the version information and exit.