Sorting Text
Emacs provides several commands for sorting text in the buffer. All operate on the contents of the region (the text between point and the mark). They divide the text of the region into many sort records, identify a sort key for each record, and then reorder the records into the order determined by the sort keys. The records are ordered so that their keys are in alphabetical order, or, for numeric sorting, in numeric order. In alphabetic sorting, all upper-case letters 'A' through 'Z' come before lower-case 'a', in accord with the ASCII character sequence.
The various sort commands differ in how they divide the text into sort records and in which part of each record is used as the sort key. Most of the commands make each line a separate sort record, but some commands use paragraphs or pages as sort records. Most of the sort commands use each entire sort record as its own sort key, but some use only a portion of the record as the sort key.
- M-x sort-lines
Divide the region into lines, and sort by comparing the entire text of a line. A numeric argument means sort into descending order. - M-x sort-paragraphs
Divide the region into paragraphs, and sort by comparing the entire text of a paragraph (except for leading blank lines). A numeric argument means sort into descending order. - M-x sort-pages
Divide the region into pages, and sort by comparing the entire text of a page (except for leading blank lines). A numeric argument means sort into descending order. - M-x sort-fields
Divide the region into lines, and sort by comparing the contents of one field in each line. Fields are defined as separated by whitespace, so the first run of consecutive non-whitespace characters in a line constitutes field 1, the second such run constitutes field 2, etc.Specify which field to sort by with a numeric argument: 1 to sort by field 1, etc. A negative argument means count fields from the right instead of from the left; thus, minus 1 means sort by the last field. If several lines have identical contents in the field being sorted, they keep the same relative order that they had in the original buffer.
- M-x sort-numeric-fields
Like M-x sort-fields except the specified field is converted to an integer for each line, and the numbers are compared. 10 comes before 2 when considered as text, but after it when considered as a number. By default, numbers are interpreted according to sort-numeric-base, but numbers beginning with 0x or 0 are interpreted as hexadecimal and octal, respectively. - M-x sort-columns
Like M-x sort-fields except that the text within each line used for comparison comes from a fixed range of columns. See below for an explanation. - M-x reverse-region
Reverse the order of the lines in the region. This is useful for sorting into descending order by fields or columns, since those sort commands do not have a feature for doing that.
For example, if the buffer contains this: [blockquote shade=no] On systems where clash detection (locking of files being edited) is implemented, Emacs
