Anchors

An anchor does not match a character; instead, it matches what comes before (or after) a character:

Description	Character	Example
Beginning of a string	^	'aba' -match '^a'
End of a string	$	'cbc' -match 'c$'
Word boundary	\b	'Band and Land' -match '\band\b'

Anchors are useful where a character, string, or word may appear elsewhere in a string and the position is critical.

For example, there might be a need to get values from the PATH environment variable that starts with a specific drive letter. One approach to this problem is to use the start of a string anchor, in this case, retrieving everything that starts with the C drive:

$env:PATH -split ';' | Where-Object { $_ -match '^C' }

Alternatively, there may be a need to get every path three or more directories deep from a set:

$env:PATH -split ';' | Where-Object { $_ -match '\\.+\\.+\\.+$' }

The word boundary matches both before and after a word. It allows a pattern to look for a specific word, rather than a string of characters that may be a word...