|  | Index Entry |  | Section | 
|---|
| 
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| ! |  |  | 
|---|
|  | ‘!’ to indicate primitive units: |  | Defining New Units | 
|  | ‘!endlocale’: |  | Localization | 
|  | ‘!endutf8’: |  | Unicode Support | 
|  | ‘!include’: |  | Units Data Files | 
|  | ‘!locale’: |  | Localization | 
|  | ‘!unitlist’: |  | Defining Unit List Aliases | 
|  | ‘!utf8’: |  | Unicode Support | 
| 
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| * |  |  | 
|---|
|  | ‘*’ operator: |  | Operators | 
|  | ‘**’ operator: |  | Operators | 
| 
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| + |  |  | 
|---|
|  | ‘+’ operator: |  | Sums and Differences of Units | 
| 
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| - |  |  | 
|---|
|  | ‘-’ as multiplication operator: |  | Backwards Compatibility | 
|  | ‘-’ as subtraction operator: |  | Sums and Differences of Units | 
|  | --check (option for :units) |  | Invoking Units | 
|  | --check-verbose (option for :units) |  | Invoking Units | 
|  | --compact (option for :units) |  | Invoking Units | 
|  | --digits (option for :units) |  | Invoking Units | 
|  | --exponential (option for :units) |  | Invoking Units | 
|  | --file (option for :units) |  | Invoking Units | 
|  | --file (option for :units) |  | Invoking Units | 
|  | --help (option for :units) |  | Invoking Units | 
|  | --info (option for :units) |  | Invoking Units | 
|  | --locale (option for :units) |  | Invoking Units | 
|  | --log (option for :units) |  | Invoking Units | 
|  | --minus (option for :units) |  | Invoking Units | 
|  | --newstar (option for :units) |  | Invoking Units | 
|  | --oldstar (option for :units) |  | Invoking Units | 
|  | --one-line (option for :units) |  | Invoking Units | 
|  | --output-format (option for :units) |  | Invoking Units | 
|  | --product (option for :units) |  | Invoking Units | 
|  | --quiet (option for :units) |  | Invoking Units | 
|  | --silent (option for :units) |  | Invoking Units | 
|  | --strict (option for :units) |  | Invoking Units | 
|  | --terse (option for :units) |  | Invoking Units | 
|  | --unitsfile (option for :units) |  | Invoking Units | 
|  | --verbose (option for :units) |  | Invoking Units | 
|  | --verbose-check (option for :units) |  | Invoking Units | 
|  | --version (option for :units) |  | Invoking Units | 
|  | -1 (option for :units) |  | Invoking Units | 
|  | -c (option for :units) |  | Invoking Units | 
|  | -d (option for :units) |  | Invoking Units | 
|  | -e (option for :units) |  | Invoking Units | 
|  | -f (option for :units) |  | Invoking Units | 
|  | -f (option for :units) |  | Invoking Units | 
|  | -h (option for :units) |  | Invoking Units | 
|  | -I (option for :units) |  | Invoking Units | 
|  | -L (option for :units) |  | Invoking Units | 
|  | -l (option for :units) |  | Invoking Units | 
|  | -m (option for :units) |  | Invoking Units | 
|  | -o (option for :units) |  | Invoking Units | 
|  | -p (option for :units) |  | Invoking Units | 
|  | -q (option for :units) |  | Invoking Units | 
|  | -s (option for :units) |  | Invoking Units | 
|  | -t (option for :units) |  | Invoking Units | 
|  | -U (option for :units) |  | Invoking Units | 
|  | -v (option for :units) |  | Invoking Units | 
|  | -V (option for :units) |  | Invoking Units | 
| 
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| ? |  |  | 
|---|
|  | ‘?’ for unit completion with readline: |  | Readline Support | 
|  | ‘?’ to show conformable units: |  | Interactive Use | 
| 
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| _ |  |  | 
|---|
|  | ‘_’ to use result of previous conversion: |  | Previous Result | 
| 
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| | |  |  | 
|---|
|  | ‘|’ operator: |  | Operators | 
| 
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| A |  |  | 
|---|
|  | abrasive grit size: |  | Other Nonlinear Units | 
|  | addition of units: |  | Sums and Differences of Units | 
|  | additional units data files: |  | Units Data Files | 
| 
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| B |  |  | 
|---|
|  | backwards compatibility: |  | Backwards Compatibility | 
|  | British Imperial measure: |  | Unit Definitions | 
| 
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| C |  |  | 
|---|
|  | circle, area of: |  | Other Nonlinear Units | 
|  | command, ‘!’ to indicate primitive units: |  | Defining New Units | 
|  | command, ‘!endlocale’: |  | Localization | 
|  | command, ‘!endutf8’: |  | Unicode Support | 
|  | command, ‘!endvar’: |  | Localization | 
|  | command, ‘!include’: |  | Units Data Files | 
|  | command, ‘!locale’: |  | Localization | 
|  | command, ‘!message’: |  | Localization | 
|  | command, ‘!set’: |  | Localization | 
|  | command, ‘!unitlist’: |  | Defining Unit List Aliases | 
|  | command, ‘!utf8’: |  | Unicode Support | 
|  | command, ‘!var’: |  | Localization | 
|  | command, ‘!varnot’: |  | Localization | 
|  | command-line options: |  | Invoking Units | 
|  | command-line unit conversion: |  | Command Line Use | 
|  | commands in units database: |  | Database Syntax | 
|  | compatibility: |  | Backwards Compatibility | 
|  | compatibility with earlier versions: |  | Backwards Compatibility | 
|  | completion, unit, using ‘?’ ( readlineonly): |  | Readline Support | 
|  | conformable units, ‘?’ to show: |  | Interactive Use | 
|  | currency, updating: |  | Currency | 
| 
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| D |  |  | 
|---|
|  | Darcy–Weisbach equation: |  | Complicated Unit Expressions | 
|  | data files: |  | Data Files | 
|  | data files, additional: |  | Units Data Files | 
|  | database syntax summary: |  | Database Syntax | 
|  | defining nonlinear units: |  | Defining Nonlinear Units | 
|  | defining piecewise linear units: |  | Piecewise Linear Units | 
|  | defining prefixes: |  | Defining New Units | 
|  | defining unit list aliases: |  | Defining Unit List Aliases | 
|  | defining units: |  | Defining New Units | 
|  | defining units with ‘-’: |  | Backwards Compatibility | 
|  | differences of units: |  | Sums and Differences of Units | 
|  | dimensionless units: |  | Interactive Use | 
|  | dimensionless units, defining: |  | Defining New Units | 
|  | division of numbers: |  | Operators | 
|  | division of units: |  | Operators | 
|  | domain, nonlinear unit definitions: |  | Defining Nonlinear Units | 
| 
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| E |  |  | 
|---|
|  | environment dependent definitions: |  | Localization | 
|  | environment variable, HOME: |  | Environment Vars | 
|  | environment variable, LANG: |  | Environment Vars | 
|  | environment variable, LC_CTYPE: |  | Environment Vars | 
|  | environment variable, MYUNITSFILE: |  | Units Data Files | 
|  | environment variable, MYUNITSFILE: |  | Environment Vars | 
|  | environment variable, PAGER: |  | Environment Vars | 
|  | environment variable, UNITSFILE: |  | Environment Vars | 
|  | environment variable, UNITSLOCALEMAP: |  | Environment Vars | 
|  | environment variable, UNITS_ENGLISH: |  | Environment Vars | 
|  | environment variables: |  | Environment Vars | 
|  | exchange rates, updating: |  | Currency | 
|  | exponent operator: |  | Operators | 
| 
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| F |  |  | 
|---|
|  | files, data: |  | Data Files | 
|  | flags, output format: |  | Flags | 
|  | format specification, output: |  | Format Specification | 
|  | fractions, numerical: |  | Operators | 
|  | functions of units: |  | Defining Nonlinear Units | 
|  | functions, built in: |  | Built-in Functions | 
| 
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| H |  |  | 
|---|
|  | help: |  | Interactive Use | 
|  | help: |  | Environment Vars | 
|  | HOME environment variable: |  | Environment Vars | 
|  | hyphen as multiplication operator: |  | Backwards Compatibility | 
| 
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| I |  |  | 
|---|
|  | Imperial measure: |  | Unit Definitions | 
|  | include files: |  | Defining New Units | 
|  | including additional units data files: |  | Units Data Files | 
|  | incompatible units: |  | Interactive Use | 
|  | interactive use: |  | Interactive Use | 
|  | international mile: |  | Unit Definitions | 
|  | international yard: |  | Unit Definitions | 
|  | invoking units: |  | Invoking Units | 
| 
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| L |  |  | 
|---|
|  | LANG environment variable: |  | Environment Vars | 
|  | LC_CTYPE environment variable: |  | Environment Vars | 
|  | length measure, English customary: |  | Unit Definitions | 
|  | length measure, UK: |  | Unit Definitions | 
|  | linear interpolation: |  | Piecewise Linear Units | 
|  | locale: |  | Locale | 
|  | locale_map.txt: |  | Locale | 
|  | localization: |  | Localization | 
|  | log file: |  | Logging Calculations | 
|  | logging calculations: |  | Logging Calculations | 
| 
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| M |  |  | 
|---|
|  | measure, Imperial: |  | Unit Definitions | 
|  | mile, international: |  | Unit Definitions | 
|  | minus (‘-’) operator, subtraction: |  | Sums and Differences of Units | 
|  | multiplication of units: |  | Operators | 
|  | multiplication, hyphen: |  | Backwards Compatibility | 
|  | MYUNITSFILE environment variable: |  | Units Data Files | 
|  | MYUNITSFILE environment variable: |  | Environment Vars | 
| 
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| N |  |  | 
|---|
|  | non-conformable units: |  | Interactive Use | 
|  | non-interactive unit conversion: |  | Command Line Use | 
|  | nonlinear unit conversions: |  | Nonlinear Conversions | 
|  | nonlinear unit conversions: |  | Defining Nonlinear Units | 
|  | nonlinear units, defining: |  | Defining Nonlinear Units | 
|  | nonlinear units, other: |  | Other Nonlinear Units | 
|  | numbers as units: |  | Numbers as Units | 
|  | numeric output format: |  | Numeric Output Format | 
|  | numerical fractions: |  | Operators | 
| 
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| O |  |  | 
|---|
|  | operator precedence: |  | Operators | 
|  | operator, (‘**’): |  | Operators | 
|  | operator, caret (‘^’): |  | Operators | 
|  | operator, hyphen (‘-’) as multiplication: |  | Backwards Compatibility | 
|  | operator, hyphen (‘-’) as subtraction: |  | Sums and Differences of Units | 
|  | operator, minus (‘-’): |  | Sums and Differences of Units | 
|  | operator, ‘per’: |  | Operators | 
|  | operator, plus (‘+’): |  | Sums and Differences of Units | 
|  | operator, slash (‘/’): |  | Operators | 
|  | operator, solidus (‘/’): |  | Operators | 
|  | operator, space: |  | Operators | 
|  | operator, star (‘*’): |  | Operators | 
|  | operator, vertical bar (‘|’): |  | Operators | 
|  | operators: |  | Operators | 
|  | output field width: |  | Field Width | 
|  | output format: |  | Numeric Output Format | 
|  | output format flags: |  | Flags | 
|  | output format specification: |  | Format Specification | 
|  | output precision: |  | Precision | 
| 
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| P |  |  | 
|---|
|  | PAGER environment variable: |  | Environment Vars | 
|  | parentheses: |  | Operators | 
|  | parentheses: |  | Operators | 
|  | parentheses: |  | Operators | 
|  | parentheses: |  | Sums and Differences of Units | 
|  | parentheses: |  | Complicated Unit Expressions | 
|  | parentheses: |  | Defining New Units | 
|  | parentheses: |  | Defining New Units | 
|  | parentheses: |  | Defining Nonlinear Units | 
|  | ‘per’ operator: |  | Operators | 
|  | personal units data file: |  | Units Data Files | 
|  | piecewise linear units: |  | Piecewise Linear Units | 
|  | plus (‘+’) operator: |  | Sums and Differences of Units | 
|  | powers: |  | Operators | 
|  | precision, output: |  | Precision | 
|  | prefixes: |  | Unit Definitions | 
|  | prefixes and exponents: |  | Operators | 
|  | prefixes, definition of: |  | Defining New Units | 
|  | previous result: |  | Previous Result | 
|  | primitive units: |  | Defining New Units | 
|  | products of units: |  | Operators | 
| 
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| Q |  |  | 
|---|
|  | quotients of units: |  | Operators | 
| 
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| R |  |  | 
|---|
|  | range, nonlinear unit definitions: |  | Defining Nonlinear Units | 
|  | readline, use withunits: |  | Readline Support | 
|  | reciprocal conversion: |  | Interactive Use | 
|  | roots: |  | Built-in Functions | 
| 
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| S |  |  | 
|---|
|  | setlocale function: |  | Locale | 
|  | slash (‘/’) operator: |  | Operators | 
|  | solidus (‘/’) operator: |  | Operators | 
|  | sphere, volume of: |  | Other Nonlinear Units | 
|  | square roots: |  | Built-in Functions | 
|  | star (‘*’) operator: |  | Operators | 
|  | State Plane Coordinate System, US: |  | Unit Definitions | 
|  | strict conversion: |  | Interactive Use | 
|  | subtraction of units: |  | Sums and Differences of Units | 
|  | sums and differences of units: |  | Sums and Differences of Units | 
|  | sums of units: |  | Sums and Differences of Units | 
|  | sums of units: |  | Unit Lists | 
|  | survey foot, US: |  | Unit Definitions | 
|  | survey measure, US: |  | Unit Definitions | 
|  | survey mile, US: |  | Unit Definitions | 
|  | syntax of units database: |  | Database Syntax | 
| 
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| T |  |  | 
|---|
|  | temperature conversions: |  | Temperature Conversions | 
| 
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| U |  |  | 
|---|
|  | Unicode support: |  | Unicode Support | 
|  | unit completion using ‘?’ ( readlineonly): |  | Readline Support | 
|  | unit definitions: |  | Unit Definitions | 
|  | unit expressions: |  | Unit Expressions | 
|  | unit expressions, complicated: |  | Complicated Unit Expressions | 
|  | unit list aliases, defining: |  | Defining Unit List Aliases | 
|  | unit lists: |  | Unit Lists | 
|  | unit name completion: |  | Readline Support | 
|  | units data file, personal: |  | Units Data Files | 
|  | units data files, additional: |  | Units Data Files | 
|  | units definitions, adding: |  | Defining New Units | 
|  | units definitions, changing: |  | Defining New Units | 
|  | units functions: |  | Defining Nonlinear Units | 
|  | units quotients: |  | Operators | 
|  | units, definition of: |  | Defining New Units | 
|  | units, lookup method: |  | Unit Definitions | 
|  | units, piecewise linear: |  | Piecewise Linear Units | 
|  | units, primitive: |  | Defining New Units | 
|  | units, sums and differences: |  | Sums and Differences of Units | 
|  | units, sums of: |  | Unit Lists | 
|  | UNITSFILE environment variable: |  | Environment Vars | 
|  | UNITSLOCALEMAP environment variable: |  | Environment Vars | 
|  | UNITS_ENGLISH environment variable: |  | Environment Vars | 
|  | US State Plane Coordinate System: |  | Unit Definitions | 
|  | US survey foot: |  | Unit Definitions | 
|  | US survey measure: |  | Unit Definitions | 
|  | US survey mile: |  | Unit Definitions | 
|  | UTF-8: |  | Unicode Support | 
| 
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| V |  |  | 
|---|
|  | verbose output: |  | Interactive Use | 
|  | verbose output: |  | Interactive Use | 
|  | vertical bar (‘|’) operator: |  | Operators | 
|  | volume measure, English customary: |  | Unit Definitions | 
| 
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| W |  |  | 
|---|
|  | wire gauge: |  | Other Nonlinear Units | 
| 
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| Y |  |  | 
|---|
|  | yard, international: |  | Unit Definitions | 
| 
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