NAME

watchdiff - repeat command and watch differences

VERSION

Version 4.49

SYNOPSIS

  watchdiff option -- command

OPTIONS:

  -r, --refresh:1     refresh screen count (default 1)
  -i, --interval=i    interval time in second (default 2)
  -c, --count=i       command repeat count (default 1000)
  -e, --exec=s        set executing commands
  -s, --silent        do not show same result
  -p, --plain         shortcut for --nodate --nonewline
  --[no-]date         show date at the beginning (default on)
  --[no-]newline      print newline after result (default on)
  --[no-]clear        clear screen after output (default on)
  --diff=command      diff command used to compare result
  --unit=unit         comparison unit (word/letter/char/mecab)

  -V, --verbose       print diff control command (default off)
  -M, --mark          show diff mark (default off)
  -O, --old           show old data (default off)
  -C[#],--context=#   diff before/after context (default 2)
  -S, --scroll        set scroll region (default on)

  -h, --help          show help
  --version           show version

DESCRIPTION

watchdiff repeatedly executes the given command and shows how its output changes, highlighting the difference from the previous run. Use ^C to terminate.

The command basically expects the output to be small enough to fit on the terminal screen. If the output is taller than the screen, only the final part is shown.

Use the -C# option if the output is large and you want to see only the modified part.

OPTIONS

What to run

-e command, --exec=command

Set the command to execute. The option can be repeated; the output of all the commands is joined together and compared as a whole.

watchdiff -e uptime -e iostat -e df

The command can also be written after the options. Put -- in front of it if it takes options of its own.

-c count, --count=count

Repeat the command count times, then exit. Default is 1000.

-i second, --interval=second

Wait second seconds between executions. Default is 2.

How the screen is used

-r[count], --refresh[=count]

Clear the screen every count executions, so the result stays at the top of the screen. Default is 1, clearing every time. With -r0 the screen is never cleared and the results simply scroll by.

--[no-]clear

Erase the rest of the screen after the result is printed, so that a longer result from an earlier round does not stay behind. Effective only while refreshing. Default on.

-S, --[no-]scroll

Set the scroll area from the third line of the screen to the bottom edge, leaving the date header in place. This takes effect only when the date is shown and the screen is refreshed every time. Default on.

-s, --[no-]silent

While the result does not change, do not print it again; only the date is updated in place. Default off.

--[no-]date

Print the date in front of each result. Default on.

--[no-]newline

Print a newline after the result. Default on.

-p, --plain

Shortcut for --no-date --no-newline.

How the difference is shown

-C[context], --context=context, -Ucontext

Show context lines before and after the updated part, instead of the whole result. Bare -C means 2. Any context under 100 also turns on the --verbose option; use --no-verbose to keep it off.

-V, --[no-]verbose

Print the control lines of the diff output. Default off.

-M, --[no-]mark

Print the diff mark at the head of each line. Default off.

-O, --[no-]old

Print the old text as well as the new one. Default off.

--unit=unit, --by=unit

Set the unit of comparison, passed through to cdif. Choose from word (default), letter, char or mecab.

--cm=colormap, --colormap=colormap

Set the colors used for the difference. The labels are APPEND, DELETE, OCHANGE, NCHANGE, OTEXT and NTEXT, and the values are handed to cdif. See "--colormap" in cdif for the format.

--diff=command

Compare the two results with command instead of the built-in cdif call. The command is given the two file names as its last two arguments. Note that the options above that are implemented by passing something to cdif have no effect once this is set.

watchdiff -ps --diff=sdif netstat -sp ip

Others

-h, --help

Show the summary above and exit.

--version

Show the version number and exit.

EXAMPLES

watchdiff df

watchdiff --silent df

watchdiff --refresh 5 --noclear df

watchdiff ifconfig en0

watchdiff -sri1 -- netstat -sp ip

watchdiff -ps --diff=sdif netstat -sp ip

watchdiff -e uptime -e iostat -e df

watchdiff -pc18i10r0 date; say -v Alex Ramen is ready

watchdiff -sU2 du -h ~/Music

AUTHOR

Kazumasa Utashiro

https://github.com/kaz-utashiro/sdif-tools

LICENSE

Copyright 2014-2026 Kazumasa Utashiro

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

App::sdif

diff(1), cdif(1), sdif(1)