About Special Characters

SHORT DESCRIPTION

Describes the special characters that you can use to control how Windows PowerShell interprets the next character in a command or parameter.

LONG DESCRIPTION

PowerShell supports a set of special character sequences that are used to represent characters that are not part of the standard character set.

The special characters in PowerShell begin with the backtick character, also known as the grave accent (ASCII 96).

The following special characters are recognized by PowerShell:

| Character | Description             |
| --------- | ----------------------- |
| `0        | Null                    |
| `a        | Alert                   |
| `b        | Backspace               |
| `e        | Escape                  |
| `f        | Form feed               |
| `n        | New line                |
| `r        | Carriage return         |
| `t        | Horizontal tab          |
| `u{x}     | Unicode escape sequence |
| `v        | Vertical tab            |
| --%       | Stop parsing            |

These characters are case-sensitive. The escape character is only interpreted when used within double quoted (") strings.

NULL (`0)

PowerShell recognizes a null special character (`0) and represents it with a character code of 0. It appears as an empty space in the Windows PowerShell output. This allows you to use PowerShell to read and process text files that use null characters, such as string termination or record termination indicators. The null special character is not equivalent to the $null variable, which stores a value of NULL.

ALERT (`a)

The alert (`a) character sends a beep signal to the computer's speaker. You can use this to warn a user about an impending action. The following command sends two beep signals to the local computer's speaker:

for ($i = 0; $i -le 1; $i++){"`a"}

BACKSPACE (`b)

The backspace character (`b) moves the cursor back one character, but it does not delete any characters. The following command writes the word "backup", moves the cursor back twice, and then writes the word "out" (preceded by a space and starting at the new position):

"backup`b`b out"

The output from this command is as follows:

back out

ESCAPE (`e)

The escape character is most commonly used to specify a virtual terminal sequence (ANSI escape sequence) that modifies the color of text and other text attributes such as bolding and underlining. These sequences can also be used for cursor positioning and scrolling. The PowerShell host must support virtual terminal sequences. This can be checked on PowerShell v5 and higher with the boolean property $Host.UI.SupportsVirtualTerminal.

For more information about ANSI escape sequences, see http://en.wikipedia.org/wiki/ANSI_escape_code

The following command outputs Green text.

$fgColor = 32 # green
"`e[${fgColor}mGreen text`e[0m"

The output from this command is the following text with a Green foreground color:

Green text

FORM FEED (`f)

The form feed character (`f) is a print instruction that ejects the current page and continues printing on the next page. This character affects printed documents only; it does not affect screen output.

NEW LINE (`n)

The new line character (`n) inserts a line break immediately after the character.

The following example shows how to use the new line character in a Write-Host command:

"There are two line breaks`n`nhere."

The output from this command is as follows:

There are two line breaks

here.

CARRIAGE RETURN (`r)

The carriage return character (`r) eliminates the entire line prior to the `r character, as though the prior text were on a different line.

For example:

Write-Host "Let's not move`rDelete everything before this point."

The output from this command is:

Delete everything before this point.

HORIZONTAL TAB (`t)

The horizontal tab character (`t) advances to the next tab stop and continues writing at that point. By default, the PowerShell console has a tab stop at every eighth space.

For example, the following command inserts two tabs between each column.

"Column1`t`tColumn2`t`tColumn3"

The output from this command is:

Column1         Column2         Column3

UNICODE CHARACTER (`u{x})

The Unicode escape sequence allows you to specify any Unicode character by the hexadecimal representation of its code point. This includes Unicode characters above the Basic Multilingual Plane (> 0xFFFF) which includes emoji characters e.g. `u{1F44D}. The Unicode escape sequence requires at least one hex digit and supports up to six hex digits. The maximum hex value for the sequence is 10FFFF.

The following command outputs the character '↕':

"`u{2195}"

VERTICAL TAB (`v)

The horizontal tab character (`t) advances to the next vertical tab stop and writes all subsequent output beginning at that point. This character affects printed documents only. It does not affect screen output.

STOP PARSING (--%)

The stop-parsing symbol (--%) prevents PowerShell from interpreting arguments in program calls as PowerShell commands and expressions.

Place the stop-parsing symbol after the program name and before program arguments that might cause errors.

For example, the following Icacls command uses the stop-parsing symbol.

icacls X:\VMS --% /grant Dom\HVAdmin:(CI)(OI)F

PowerShell sends the following command to Icacls.

X:\VMS /grant Dom\HVAdmin:(CI)(OI)F

For more information about the stop-parsing symbol, see about_Parsing.

SEE ALSO