applying M-x sort-lines to the entire buffer produces this:
On systems where clash detection (locking of files being edited) is implemented, Emacs also checks the first time you modify a buffer saved. If it has, you are asked to confirm that you want to change the buffer. whether the file has changed on disk since it was last visited or
where the upper-case O sorts before all lower-case letters. If you use C-u 2 M-x sort-fields instead, you get this:
implemented, Emacs also checks the first time you modify a buffer saved. If it has, you are asked to confirm that you want to change the buffer. On systems where clash detection (locking of files being edited) is whether the file has changed on disk since it was last visited or
where the sort keys were Emacs, If, buffer, systems and the.
M-x sort-columns requires more explanation. You specify the columns by putting point at one of the columns and the mark at the other column. Because this means you cannot put point or the mark at the beginning of the first line of the text you want to sort, this command uses an unusual definition of "region": all of the line point is in is considered part of the region, and so is all of the line the mark is in, as well as all the lines in between.
For example, to sort a table by information found in columns 10 to 15, you could put the mark on column 10 in the first line of the table, and point on column 15 in the last line of the table, and then run sort-columns. Equivalently, you could run it with the mark on column 15 in the first line and point on column 10 in the last line.
This can be thought of as sorting the rectangle specified by point and the mark, except that the text on each line to the left or right of the rectangle moves along with the text inside the rectangle. See Rectangles.
Many of the sort commands ignore case differences when comparing, if sort-fold-case is non-nil.
