Ispell is a program that helps you to correct typos in a file, and to find the correct spelling of words. When presented with a word that is not in the dictionary, ispell attempts to find near misses that might include the word you meant.
The best way to use ispell is with GNU EMACS. For documentation about this mode, see the info topic "ispell".
Ispell can also be used by itself, and in this case the most common usage is "ispell filename". If ispell finds a word that is not in the dictionary, it is printed at the top of the screen. Ispell then checks the dictionary for near misses - words that differ only by a single letter, a missing or extra letter, or a pair of transposed letters. Any that are found are printed on the following lines, and finally, two lines of context containing the word are printed at the bottom of the screen. If your terminal can type in reverse video, the word itself is highlighted.
If you think the word is correct as it stands, you can type either "Space" to accept it this one time, "A" to accept it for the rest of this file, or "I" to accept it and put it in your private dictionary. If one of the near misses is the word you want, type the corresponding number. Finally, you can type "R" and you will be prompted for a replacement word. The string you type will be broken into words, and each one will also be checked. You can also type "?" for help.
If ispell is started with no arguments, it enters a loop reading words from the standard input, and printing messages about them on the standard output. You can use this mode to find the spelling of a problem word. For example:
You can print out the system dictionary. Use -D if you want flags, or -E if you want the words expanded.
% ispell word: independant how about: independent word: ^D
The -l or "list" option to ispell is used to produce a list of misspelled words from the standard input. This mode is compatible with the traditional spell program, except that the output is not sorted.
There are several other options provided so that other programs can use ispell. See the documentation in the ispell source directory for details.
If ispell is executed with the name `spell', it attempts to be compatible with the traditional spell program. You can also get this behavior with the -u flag. In this case, the list of files (or standard input) is checked, and an alphabetized list of misspellings is produced on the standard output.