diffmk(1) — Commands
NAME
diffmk − Marks differences between files
SYNOPSIS
diffmk [-b] [-ab’mark’] [-ae’mark’] [-cb’mark’] [-ce’mark’] [-db’mark’] [-de’mark’] file1 file2
The diffmk command compares two versions of a file and creates a new file that marks the differences.
FLAGS
-ab’mark’Uses mark to mark where added lines begin.
-ae’mark’Uses mark to mark where added lines end.
-bIgnores differences that are only changes in tabs or spaces on a line.
-cb’mark’Uses mark to mark where changed lines begin.
-ce’mark’Uses mark to mark where changed lines end.
-db’mark’Uses mark to mark where deleted lines begin.
-de’mark’Uses mark to mark where deleted lines end.
DESCRIPTION
The file1 and file2 variables are the old and new versions of the file, respectively. The diffmk command compares them and writes a new version to standard output, which can be redirected to a file. This output contains the lines of file2 marked with nroff change mark requests (.mc), or with the marks you specify with the -ab, -ae, -cb, -ce, -db, and -de flags.
When output containing .mc requests is formatted with nroff, changed or inserted lines are marked by a | (vertical bar) at the right margin of each line. An ∗ (asterisk) indicates that a line was deleted.
If the DIFFMARK environment variable is defined, it names a command string that diffmk uses to compare the files. (Normally, diffmk uses the diff command.) For example, you might set DIFFMARK to diff -h in order to better handle extremely large files.
EXAMPLES
1.To mark the differences between two versions of a text file, enter:
diffmk -ab’>I:’ -ae’<I’ -cb’>C’ -ce’<C’ -db’>D’ -de’<D’ \
chap1.old chap1 >chap1.diffs
This causes diffmk to create a copy of chap1 called chap1.diffs, showing differences between chap1.old and chap1. Additions of one or more lines are marked with >I and <I, changed lines are marked with >C and <C, and deletions are marked with >D and <D.
2.To mark differences with nroff requests, enter:
diffmk chap1.old chap1 > chap1.nroff
This produces a copy of chap1 called chap1.nroff containing nroff change mark requests to identify text that was added to, changed, or deleted from chap1.old.
3.To use different nroff marking requests and ignore changes in white space, enter:
diffmk -b -cb’.mc %’ chap1.old chap1 > chap1.nroff
This imbeds commands that mark changes with % (percent sign), additions with | (the default, because no -a flag is specified), and deletions with ∗ (the default). It does not mark changes that only involve a different number of spaces or tabs between words (-b).
RELATED INFORMATION
Commands: diff(1).