mjhjmtu

I am using a simple combination of commands to "monitor" a bit of my filesystem change: watch and tree.

Except I want colours and can't get it.

Here's what I thought should work: watch --color 'tree -C' which kind of works since it gives me some colours, but not in the same way as tree -C by itself.

Here's some screencaps:
watch --color 'tree -C' output, with some colours applying
watch 'tree -C' output, showing that tree does indeed send all escape codes
tree -C output, expected result

Culprit might also be in my env variables, but if I watch 'echo $LS_COLORS', my conf is there.

Any ideas? :)

The basic problem is that watch and tree use different information for getting the colors:

• The watch program interprets standard (ECMA-48) escape sequences for specifying video attributes. That means 8 colors, plus bold, blink, underline, reverse and italics. It uses (n)curses to display the information, making the result depend on the terminal database




• The tree program mimics GNU ls, using the LS_COLORS environment variable. That uses the TERM environment variable (which curses and most other terminal applications use to identify an entry in the terminal database) to select a set of customized escape sequences, which do not necessarily have any relationship to the terminal database's descriptions.

With some work, you could make those match, e.g., by generating a suitable LS_COLORS for a given terminal entry. Apparently no one has done that. And since the contents of LS_COLORS incomplete (covering only a small fraction of a terminal description: no function keys, no cursor movement, no generality), there is no point in generating a terminal entry from LS_COLORS.

If tree uses 256 colors, watch may not understand those codes (a recent change addresses a part of this issue for procps top but has not been adapted for watch — wait a while). watch uses (n)curses to manage the screen, which makes it necessary (for watch) to translate escape-codes into curses-calls.

Further reading:

• How do I get color with VT100?


• 
  Applications miscited as library users


• The Tree Command for Linux Homepage


• procps (watch development)