Powershell removing characters from string up to last separator

What about using split-path?

$string = 'Projects\TestEnvironment\11111xx\1111111'
Split-Path $string -Leaf

returns 1111111.

Note the -Leaf parameter indicates that this cmdlet returns only the last item or container in the path.

@Robin's answer is good if the string is always a path (separated with "\"); in the general case, where the delimiter may be a different character, you can use

$string = "This-is-a-string-with-delimiters"
$lastword = ($string -split "-")[-1]

The -split operator defaults to splitting on a space, but will split on any character you choose to pass it, returning an array of strings, each string being the material before/between/after delimiters - in the example above, each word would be in a separate string in the array. Negative subscripts to an array count from the end of the array rather than the start, and are 1-origin rather than 0-origin - so $x[-1] is the last element of the array $x.

This technique also works on paths;

$path = "C:\Users\JSmith\Documents\Resume.doc"
$filename = ($path -split "\\")[-1]

will give you $filename -eq Resume.doc. Note that the delimiter passed to -split in this case is escaped, because the delimiter can be a regular expression, and the backslash ("\") is meaningful in regular expressions (it's the character that indicates that another meaningful character is to be "escaped", or its meaning ignored).

other solution

('Projects\TestEnvironment\11111xx\1111111' -split '\\')[-1]

or

'Projects\TestEnvironment\11111xx\1111111'.Split('\')[-1]