# string - Manipulate strings

## SYNOPSIS

string option arg ?arg ...?

## DESCRIPTION

Performs one of several string operations, depending on option. The legal options (which may be abbreviated) are:

string compare string1 string2
  Perform a character-by-character comparison of strings string1 and string2 in the same way as the C strcmp procedure. Return -1, 0, or 1, depending on whether string1 is lexicographically less than, equal to, or greater than string2.

string first string1 string2
  Search string2 for a sequence of characters that exactly match the characters in string1. If found, return the index of the first character in the first such match within string2. If not found, return -1.

string index string charIndex
  Returns the charIndex'th character of the string argument. A charIndex of 0 corresponds to the first character of the string. If charIndex is less than 0 or greater than or equal to the length of the string then an empty string is returned.

string last string1 string2
  Search string2 for a sequence of characters that exactly match the characters in string1. If found, return the index of the first character in the last such match within string2. If there is no match, then return -1.

string length string
  Returns a decimal string giving the number of characters in string.

string match pattern string
  See if pattern matches string; return 1 if it does, 0 if it doesn't. Matching is done in a fashion similar to that used by the C-shell. For the two strings to match, their contents must be identical except that the following special sequences may appear in pattern:

*
Matches any sequence of characters in string, including a null string.

?
Matches any single character in string.

[chars]
Matches any character in the set given by chars. If a sequence of the form x-y appears in chars, then any character between x and y, inclusive, will match.

\x
Matches the single character x. This provides a way of avoiding the special interpretation of the characters *?[]\ in pattern.

string range string first last
  Returns a range of consecutive characters from string, starting with the character whose index is first and ending with the character whose index is last. An index of 0 refers to the first character of the string. Last may be end (or any abbreviation of it) to refer to the last character of the string. If first is less than zero then it is treated as if it were zero, and if last is greater than or equal to the length of the string then it is treated as if it were end. If first is greater than last then an empty string is returned.

string tolower string
  Returns a value equal to string except that all upper case letters have been converted to lower case.

string toupper string
  Returns a value equal to string except that all lower case letters have been converted to upper case.

string trim string ?chars?
  Returns a value equal to string except that any leading or trailing characters from the set given by chars are removed. If chars is not specified then white space is removed (spaces, tabs, newlines, and carriage returns).

string trimleft string ?chars?
  Returns a value equal to string except that any leading characters from the set given by chars are removed. If chars is not specified then white space is removed (spaces, tabs, newlines, and carriage returns).

string trimright string ?chars?
  Returns a value equal to string except that any trailing characters from the set given by chars are removed. If chars is not specified then white space is removed (spaces, tabs, newlines, and carriage returns).

string wordend string index
  Returns the index of the character just after the last one in the word containing character index of string. A word is considered to be any contiguous range of alphanumeric or underscore characters, or any single character other than these.

string wordstart string index
  Returns the index of the first character in the word containing character index of string. A word is considered to be any contiguous range of alphanumeric or underscore characters, or any single character other than these.

## KEYWORDS

case conversion, compare, index, match, pattern, string, word