---
name: "look"
section: "1plan9"
platform: "linux"
package: "9base"
version: "1:6-14"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/look/1plan9"
---

# look(1plan9)

find lines in a sorted list

## NAME

look - find lines in a sorted list

## SYNOPSIS

**look** \[ **-dfnixt***c* \] \[ *string* \] \[ *file* \]

## DESCRIPTION

*Look* consults a sorted *file* and prints all lines that begin with *string*. It uses binary search.

The following options are recognized. Options **dfnt** affect comparisons as in [*sort*(1)](/sort/1.md).

- **-i**

  Interactive. There is no *string* argument; instead *look* takes lines from the standard input as strings to be looked up.

- **-x**

  Exact. Print only lines of the file whose key matches *string* exactly.

- **-d**

  \`Directory' order: only letters, digits, tabs and blanks participate in comparisons.

- **-f**

  Fold. Upper case letters compare equal to lower case.

- **-n**

  Numeric comparison with initial string of digits, optional minus sign, and optional decimal point.

- **-t**\[***c***\]

  Character *c* terminates the sort key in the *file*. By default, tab terminates the key.  If *c* is missing the entire line comprises the key.

If no *file* is specified, **/lib/words** is assumed, with collating sequence **df**.

## FILES

**/lib/words**

## SOURCE

**/src/cmd/look.c**

## SEE ALSO

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

## DIAGNOSTICS

The exit status is \`\`**not found**'' if no match is found, and \`\`**no dictionary**'' if *file* or the default dictionary cannot be opened.