How to use look command in Linux.

Posted on September 15, 2023 by nexonhost

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.

Syntax:

look [-bdf] [-t termchar] string [file ...]

Options:

-[string]: This option is used to search for the given string in a specified file.
Example:
```
look "include" Assignment.c
```
-f : This option is used to ignore case of alphabetic character.
Example:
```
look -f ab words
```
-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.
Example:
```
look -t b abu words
```
-d: This option is used to compare only alphanumeric characters.
Example:
```
look -d ab words
```
-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.
Example:
```
look -bf ab words
```
-h: This option is used to show the help message and exit.
```
look -h
```
-V: This option is used to show the version information and exit.
```
look -V
```