Narrowing Top Editing Binary Files
Two-column mode lets you conveniently edit two side-by-side columns of text. It uses two side-by-side windows, each showing its own buffer.
There are three ways to enter two-column mode:
Enter two-column mode with the current buffer on the left, and on the
right, a buffer whose name is based on the current buffer's name
This command is appropriate when the current buffer is empty or contains just one column and you want to add another column.
Split the current buffer, which contains two-column text, into two
buffers, and display them side by side (
This command is appropriate when you have a buffer that already contains two-column text, and you wish to separate the columns temporarily.
C-x 6 b buffer
Enter two-column mode using the current buffer as the left-hand buffer,
and using buffer buffer as the right-hand buffer
F2 s or C-x 6 s looks for a column separator, which
is a string that appears on each line between the two columns. You can
specify the width of the separator with a numeric argument to
F2 s; that many characters, before point, constitute the
separator string. By default, the width is 1, so the column separator
is the character before point.
When a line has the separator at the proper place,
puts the text after the separator into the right-hand buffer, and
deletes the separator. Lines that don't have the column separator at
the proper place remain unsplit; they stay in the left-hand buffer, and
the right-hand buffer gets an empty line to correspond. (This is the
way to write a line that ``spans both columns while in two-column
mode'': write it in the left-hand buffer, and put an empty line in the
The command C-x 6
2C-newline) inserts a newline in each of the two buffers at
corresponding positions. This is the easiest way to add a new line to
the two-column text while editing it in split buffers.
When you have edited both buffers as you wish, merge them with
F2 1 or C-x 6 1 (
2C-merge). This copies the
text from the right-hand buffer as a second column in the other buffer.
To go back to two-column editing, use
F2 d or C-x 6 d to dissociate the two buffers,
leaving each as it stands (
2C-dissociate). If the other buffer,
the one not current when you type
F2 d, is empty,
F2 d kills it.