Why does iftop show 'b' characters instead of lines?

Solution 1:

Check the env variable TERM ( echo $TERM ). tmux and friends set it to 'screen' or something similar which might be unknown to the ncurses library. This runtime library is used by iftop to draw decorations and ascii windows.

Set it to something iftop accepts and call up iftop:

TERM=xterm iftop

You can set an environment variable in the commandline like above and it will only be used for this invocation of 'iftop'. That's an easy way to test.

If you're on OSX you might use xterm-256color, same for linux with xcfe-terminal running. I'm using good ol' /usr/bin/xterm, so TERM=xterm works for me.

To see all possible terminals just use toe the "table of (terminfo) entries".

Further man/google keywords: ncurses, terminfo, tic, ls -l /usr/share/terminfo/?/*