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SXEmacs provides several commands for sorting text in a 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 using the order determined by the sort keys. The records are ordered so that their keys are in alphabetical order, or, for numerical sorting, in numerical order. In alphabetical sorting, all upper-case letters ‘A’ through ‘Z’ come before lower-case ‘a’, in accordance with the ASCII character sequence.
The sort commands differ in how they divide the text into sort records and in which part of each record they use 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.
Divide the region into lines and sort by comparing the entire text of a line. A prefix argument means sort in descending order.
Divide the region into paragraphs and sort by comparing the entire text of a paragraph (except for leading blank lines). A prefix argument means sort in descending order.
Divide the region into pages and sort by comparing the entire text of a page (except for leading blank lines). A prefix argument means sort in descending order.
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.
You specify which field to sort by with a numeric argument: 1 to sort by field 1, etc. A negative argument means sort in descending order. Thus, minus 2 means sort by field 2 in reverse-alphabetical order.
Like M-x sort-fields, except the specified field is converted to a number for each line and the numbers are compared. ‘10’ comes before ‘2’ when considered as text, but after it when considered as a number.
Like M-x sort-fields, except that the text within each line used for comparison comes from a fixed range of columns. An explanation is given below.
For example, if the buffer contains:
On systems where clash detection (locking of files being edited) is implemented, SXEmacs also checks the first time you modify a buffer whether the file has changed on disk since it was last visited or saved. If it has, you are asked to confirm that you want to change the buffer.
then if you apply M-x sort-lines to the entire buffer you get:
On systems where clash detection (locking of files being edited) is implemented, SXEmacs 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’ comes before all lower case letters. If you apply instead C-u 2 M-x sort-fields you get:
saved. If it has, you are asked to confirm that you want to change implemented, SXEmacs also checks the first time you modify a buffer 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 ‘If’, ‘SXEmacs’, ‘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 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.
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 use this command. Or you could put 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.
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