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The sed FAQ
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5.3. Why does my DOS version of sed process a file part-way through and then quit?

First, look for errors in the script. Have you used the -n switch without telling sed to print anything to the console? Have you read the docs to your version of sed to see if it has a syntax you may have misused? (Look for an N or H command that gathers too much.)

Next, if you are sure your sed script is valid, a probable cause is an end-of-file marker embedded in the file. An EOF marker (SUB) is a Control-Z character, with the value of 1A hex (26 decimal). As soon as any DOS version of sed encounters a Ctrl-Z character, sed stops processing.

To locate the EOF character, use Vern Buerg's shareware file viewer LIST.COM <>. In text mode, look for a right-arrow symbol; in hex mode (Alt-H), look for a 1A code. With Unix utilities ported to DOS, use 'od' (octal dump) to display hexcodes in your file, and then use sed to locate the offending character:

       od -txC badfile.txt | sed -n "/ 1a /p; / 1a$/p"

Then edit the input file to remove the offending character(s).

If you would rather NOT edit the input file, there is still a fix. It requires the DJGPP 32-bit port of 'tr', the Unix translate program (v1.22 or higher). GNU od and tr are currently at v2.0 (for DOS); they are packaged with the GNU text utilities, available at

It is important to get the DJGPP version of 'tr' because other versions ported to DOS will stop processing when they encounter the EOF character. Use the -d (delete) command:

       tr -d \32 < badfile.txt | sed -f myscript.sed
The sed FAQ
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   Reprinted courtesy of Eric Pement. Also available at Design by Interspire