Bash – Different colour for the KiB range in `ls -l`

bashls

Is there any sane way to highlight the 4th, 5th, and 6th columns from the right of the file size in ls -l? My intention is to make it easy to read a file size be it in bytes, KiBs, or MiBs. I do know about the -h flag, but I find that having to interpret the letters at the end is more cumbersome than just looking and seeing the length of the number (magnitude). This is the same reason why race cars use analogue dials instead of digital.

My target shell is Bash. Thanks.

EDIT: I am looking to highlight the thousands, ten thousands, and one hundred thousands places of the size column. Like this: 123456789

Best Answer

Maybe something like:

ls -l | perl -pe 'BEGIN{@color=(0,2,3,1,5,4)}
  s{((?:\S+\s+){4})(\d+)}{"$1\e[3" . 
  $color[log($2||1)/log(2)/10] . "m$2\e[m"}e'

For black (or whatever the default foreground colour is on your terminal) for sizes from 0 to 1023, green from 1k to 1M, yellow for 1M to 1G, then red, purple, blue.

Edit. Based on your edited requirements:

ls -l | perl -pe 's{^((?:\S+\s+){4}\d*)(\d{3})(?=\d{3})}
                   {$1\e[31;1m$2\e[m}'

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LS Colors – How to List LS_COLORS in Colour

Try this script:

( # Run in a subshell so it won't crash current color settings
    dircolors -b >/dev/null
    IFS=:
    for ls_color in ${LS_COLORS[@]}; do # For all colors
        color=${ls_color##*=}
        ext=${ls_color%%=*}
        echo -en "\E[${color}m${ext}\E[0m " # echo color and extension
    done
    echo
)

Output:

The -F option for ls

ls -F will:

Write a ( '/' ) immediately after each pathname that is a directory, an ( '*' ) after each that is executable, a ( '|' ) after each that is a FIFO, and an at-sign ( '@' ) after each that is a symbolic link.

GNU ls includes additional signals:

... ‘=’ for sockets, ‘>’ for doors

= is also present in the major BSDs (FreeBSD, OpenBSD, NetBSD, OS X). All of those but OpenBSD also include % for whiteouts. Most of the commercial Unices include =, but it is non-standard.

A * will appear after a file if it is marked as executable — that is, if the executable bit is set. It doesn't necessarily mean you could actually run the file. You can unset the executable bit with chmod -x; generally you won't want text files and PDFs to be executable, so you could do that. Executable files will also have the x in ls -l output.

For the others:

/ indicates a directory, which is pretty straightforward.
| indicates a FIFO, which is a named pipe made with mkfifo (data can be written into it, and read back exactly once).
@ indicates a symbolic link made with ln -s, which is an alias for another path.
= indicates a socket, a special file for communicating with other processes.
> for doors is another inter-process communication feature from some systems.
% for whiteouts indicates a special file used to mark deletions made in upper layers of a union filesystem stack.

A "regular file" is what you'd conventionally think of as a file, one that you can write data into and read it back later. Alternatively, you can think of it as anything that isn't in one of the above categories.

Hard links are not distinguished from other files at all, either in ls -F output or otherwise. In fact, you can think of every file as a hard link to itself. You can look at the number of links to a given file in the ls -l output. The second field is the number of links:

-rw-r--r-- 3 root root  92766 Feb 20 11:42 test.txt

This file has three links. None of them is the "main" link, and you can't tell which one is the original in any way. If you delete one, the count will go down, but the others will still refer to the same file.

All of the -F indicators other than * do map onto one of the values of the first field of the mode output in ls -l, but there are additional values that can appear there as well, notably b for block devices, c for character devices, and other system-specific indicators.

Best Answer

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LS Colors – How to List LS_COLORS in Colour

The -F option for ls

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