---
name: "look"
section: "1"
platform: "macos"
package: "text_cmds"
version: "199"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "openbsd", "macos"]
url: "https://new.carta.tech/look"
---

# look(1)

display lines beginning with a given string

## NAME

**look** – display lines beginning with a given string

## SYNOPSIS

**look** \[**-df**\] \[**-t** *termchar*\] *string* \[*file ...*\]

## DESCRIPTION

The **look** utility displays any lines in *file* which contain *string* as a prefix. As **look** performs a binary search, the lines in *file* must be sorted.

If *file* is not specified, the file */usr/share/dict/words* is used, only alphanumeric characters are compared and the case of alphabetic characters is ignored.

The following options are available:

- **-d**, **--alphanum**

  Dictionary character set and order, i.e., only alphanumeric characters are compared.

- **-f**, **--ignore-case**

  Ignore the case of alphabetic characters.

- **-t**, **--terminate** *termchar*

  Specify a string termination character, i.e., only the characters in *string* up to and including the first occurrence of *termchar* are compared.

## ENVIRONMENT

The LANG, LC\_ALL and LC\_CTYPE environment variables affect the execution of the **look** utility. Their effect is described in [environ(7)](/environ/7.md).

## FILES

- */usr/share/dict/words*

  the dictionary

## EXIT STATUS

The **look** utility exits 0 if one or more lines were found and displayed, 1 if no lines were found, and \>1 if an error occurred.

## EXAMPLES

Look for lines starting with ‘xylene’ in the file */usr/share/dict/words*:

```
$ look xylen
xylene
xylenol
xylenyl
```

Same as above, but do not consider any characters in *string* beyond the first ‘e’. Note that **-f** is implicit since we are searching the default file */usr/share/dict/words*:

```
$ look -t e xylen
Xyleborus
xylem
xylene
xylenol
xylenyl
xyletic
```

## COMPATIBILITY

The original manual page stated that tabs and blank characters participated in comparisons when the **-d** option was specified. This was incorrect and the current man page matches the historic implementation.

The **-a** and **--alternative** flags are ignored for compatibility.

## SEE ALSO

[grep(1)](/grep/1.md), [sort(1)](/sort/1.md)

## HISTORY

A **look** utility appeared in Version 7 AT&T UNIX.

## BUGS

Lines are not compared according to the current locale's collating order. Input files must be sorted with LC\_COLLATE set to ‘C’.