Previous:Line Group Formats
Line formats control how each line taken from an input file is
output as part of a line group in if-then-else format.
For example, the following command outputs text with a one-character
change indicator to the left of the text. The first character of output
- for deleted lines,
| for added lines, and a space for
unchanged lines. The formats contain newline characters where newlines
are desired on output.
To specify a line format, use one of the following options. You should
quote format, since it often contains shell metacharacters.
- formats lines just from the first file.
- formats lines just from the second file.
- formats lines common to both files.
- formats all lines; in effect, it sets all three above options simultaneously.
In a line format, ordinary characters represent themselves;
conversion specifications start with
% and have one of the
- stands for the contents of the line, not counting its trailing
newline (if any). This format ignores whether the line is incomplete;
See Incomplete Lines.
- stands for the contents of the line, including its trailing newline
(if any). If a line is incomplete, this format preserves its
- stands for
- where C is a single character, stands for C.
C may not be a backslash or an apostrophe.
%c':' stands for a colon.
- where O is a string of 1, 2, or 3 octal digits,
stands for the character with octal code O.
%c'\0' stands for a null character.
- where F is a
printf conversion specification,
stands for the line number formatted with F.
%.5dn prints the line number using the
"%.5d". See Line Group Formats, for
more about printf conversion specifications.
The default line format is
%l followed by a newline character.
If the input contains tab characters and it is important that they line
up on output, you should ensure that
%L in a line
format is just after a tab stop (e.g. by preceding
%L with a tab character), or you should use the
Taken together, the line and line group formats let you specify many
different formats. For example, the following command uses a format
similar to normal
diff format. You can tailor this command
to get fine control over