How to make vim apply /var/log/messages syntax highlighting to any file called “messages” or “messages-*”

In addition to uprego's answer, you can press Ctrl+G (in normal mode) to get the current buffer's name as well as the total number of lines in it and your current position within it.

Update

As per rxdazn's comment, you can press 1 before Ctrl+G to get the full file path. If you press 2, you get the full file path and the buffer number you currently have open (useful when you have opened multiple files with vim).

The command in the LESSOPEN variable after the initial pipe is executed by the shell indicated by the SHELL environment variable and must produce the desired content on its standard output.

You can pass the output of lesspipe as input to another command that reads from standard input and writes to standard output. However, in order for source-highlight to read from its standard input, it needs to be told what language to highlight for, so source-highlight doesn't work this way.

When lesspipe doesn't recognized a file format, it prints nothing, which less interprets as an indication to read the original file. If you have ifne from Joey Hess's moreutils, you can use it to detect this case and try source-highlight instead. You'll need to save the original file name in a variable so that you can use it twice.

LESSOPEN='|file=%s; /usr/bin/lesspipe "$file" | /usr/bin/ifne -n /usr/bin/source-highlight -i "$file" -o STDOUT 2>/dev/null'

Note that you'll need to include -r or -R in $LESS or type -r or -R after starting less in order for less to render the colors.