by Aurelio Jargas


sedsed can debug, indent, tokenize and HTMLize your sed scripts.

In debug mode it reads your script and add extra commands to it. When executed you can see the data flow between the commands, revealing all the magic sed does on its internal buffers.

In indent mode your script is reformatted with standard spacing.

In tokenize mode you can see the elements of every command you use.

In HTMLize mode your script is converted to a beautiful colored HTML file, with all the commands and parameters identified for your viewing pleasure.

With sedsed you can master ANY sed script. No more secrets, no more hidden buffers.


Sedsed is available as a pip package, just install it:

pip install --user sedsed

Found a bug? Please submit an issue.

Alternative: sedsed is a single file application, so you can also just download and run Note that you'll also need to download its only external requirement,


prompt$ sedsed --help

usage: sedsed OPTION [-e sedscript] [-f sedscriptfile] [inputfile]


     -f, --file          add file contents to the commands to be parsed
     -e, --expression    add the script to the commands to be parsed
     -n, --quiet         suppress automatic printing of pattern space
         --silent        alias to --quiet

     -d, --debug         debug the sed script
         --hide          hide some debug info (options: PATT,HOLD,COMM)
         --color         shows debug output in colors (default: ON)
         --nocolor       no colors on debug output
         --dump-debug    dumps to screen the debugged sed script

     -i, --indent        script beautifier, prints indented and
                         one-command-per-line output do STDOUT
         --prefix        indent prefix string (default: 4 spaces)

     -t, --tokenize      script tokenizer, prints extensive
                         command by command information
     -H, --htmlize       converts sed script to a colorful HTML page


Quick sample




Besides indent and debug, sedsed also has the ability to convert your sed scripts to nice HTML pages, with the syntax highlighted just as in Vim Editor, with nice colors!

prompt$ cat email-linker.sed
h;s|.*|<link>&</link>|;x;/@/{s/@.*/'s email:/;G;}

prompt$ sedsed --htmlize -f email-linker.sed > email-linker.sed.html

Here is the resulting HTML file:

Visit the sed Website for examples of more than 60 sed scripts HTMLized.


sedsed Output
PATT: Contents of the PATTERN SPACE buffer
HOLD: Contents of the HOLD SPACE buffer
COMM: The sed command being executed
$ Terminates the PATT and HOLD contents
... Lines that don't begin with any identifiers are STDOUT
Action Options
--debug DEBUG the sed script
--indent Script beautifier, show indented source
--tokenize Script tokenizer, show info about each command
--htmlize Converts sed script to a colorful HTML page
less -r is your friend to page the colorful output of -d
Use the --hide option to a cleaner debug output
--htmlize send results to STDOUT, so redirect it


sedsed was tested successfully against all the 5 stars (*****) extreme sed scripts from the Bonzini's excellent grab-bag site. So all the sed commands and structures wrote on these scripts, which are EXTREME, are correctly parsed.

If you want to try at home, download and execute them this way:

echo -e "one\ntwo\nthree\nfour" | sedsed -d -f sodelnum.sed

echo -e "one\ntwo\nthree\nfour" | sedsed -d -f sort.sed

echo a{b{c{bla}}} | sedsed -d -f tex2xml.sed

echo "aa='abc" | sedsed -d -f config.sed

(date +'%w %d' ; date +'%-m %Y') | sedsed -d -f cal.sed

echo 4 4 + p | sedsed -d -f dc.sed

YES! Now you can (try to) understand what happens inside the unbelievable dc.sed calculator. Check this great shot of a simple "4+4" becoming "8" :)