使用xshell securecrt 時，可以自定義顏色主題檔案， 但是各個顏色塊都代表什麼意思呢？
搜尋linux下檔案顏色的含義，也沒看到一個講清楚的，比如說

藍色表示目錄；綠色表示可執行檔案；紅色表示壓縮檔案；淺藍色表示連結檔案；白色表示其他檔案；黃色是裝置檔案，包括block, char, fifo。

但是內部原理是什麼呢？現在想要改變xshell中目錄的顯示顏色，在ASNI顏色設定中 ，總共有16個顏色塊， 哪一個代表目錄的顏色呢？

如圖

ASNI定義了幾種基本顏色的編碼

Black: \u001b[30m.
Red: \u001b[31m.
Green: \u001b[32m.
Yellow: \u001b[33m.
Blue: \u001b[34m.
Magenta: \u001b[35m.
Cyan: \u001b[36m.
White: \u001b[37m.
#30（黑色）、31（紅色）、32（綠色）、 33（黃色）、34（藍色）、35（洋紅）、36（青色）、37（白色）
 

下面是個人理解， 有問題請指出
第一行每一個色塊分別對應上面的8個編碼，第二行分別對應加粗字型。

30顏色對應第一個色塊， 37顏色對應第8個色塊
例如， 把第一行第二個色塊，改為白色，表示 31 編碼的顏色，在xshell中將顯示為白色。

第三方工具的設定ASNI顏色， 本質上就是把預定好這八種顏色，顯示為其他顏色。
如果某個檔案，顏色型別為39， 超出了這八種基本顏色，則顯示為原本編碼好的ASNI顏色

不同型別檔案的ASNI顏色編碼，執行這個命令可以直接看到

[email protected]:~/1src/shell$  dircolors -p 
# Configuration file for dircolors, a utility to help you set the
# LS_COLORS environment variable used by GNU ls with the --color option.
# Copyright (C) 1996-2017 Free Software Foundation, Inc.
# Copying and distribution of this file, with or without modification,
# are permitted provided the copyright notice and this notice are preserved.
# The keywords COLOR, OPTIONS, and EIGHTBIT (honored by the
# slackware version of dircolors) are recognized but ignored.
# Below are TERM entries, which can be a glob patterns, to match
# against the TERM environment variable to determine if it is colorizable.
TERM Eterm
TERM ansi
TERM *color*
TERM con[0-9]*x[0-9]*
TERM cons25
TERM console
TERM cygwin
TERM dtterm
TERM gnome
TERM hurd
TERM jfbterm
TERM konsole
TERM kterm
TERM linux
TERM linux-c
TERM mlterm
TERM putty
TERM rxvt*
TERM screen*
TERM st
TERM terminator
TERM tmux*
TERM vt100
TERM xterm*
# Below are the color init strings for the basic file types. A color init
# string consists of one or more of the following numeric codes:
# Attribute codes:
# 00=none 01=bold 04=underscore 05=blink 07=reverse 08=concealed
# Text color codes:
# 30=black 31=red 32=green 33=yellow 34=blue 35=magenta 36=cyan 37=white
# Background color codes:
# 40=black 41=red 42=green 43=yellow 44=blue 45=magenta 46=cyan 47=white
#NORMAL 00 # no color code at all
#FILE 00 # regular file: use no color at all
RESET 0 # reset to "normal" color
DIR 01;34 # directory
LINK 01;36 # symbolic link. (If you set this to 'target' instead of a
 # numerical value, the color is as for the file pointed to.)
MULTIHARDLINK 00 # regular file with more than one link
FIFO 40;33 # pipe
SOCK 01;35 # socket
DOOR 01;35 # door
BLK 40;33;01 # block device driver
CHR 40;33;01 # character device driver
ORPHAN 40;31;01 # symlink to nonexistent file, or non-stat'able file ...
MISSING 00 # ... and the files they point to
SETUID 37;41 # file that is setuid (u+s)
SETGID 30;43 # file that is setgid (g+s)
CAPABILITY 30;41 # file with capability
STICKY_OTHER_WRITABLE 30;42 # dir that is sticky and other-writable (+t,o+w)
OTHER_WRITABLE 34;42 # dir that is other-writable (o+w) and not sticky
STICKY 37;44 # dir with the sticky bit set (+t) and not other-writable
# This is for files with execute permission:
EXEC 01;32
# List any file extensions like '.gz' or '.tar' that you would like ls
# to colorize below. Put the extension, a space, and the color init string.
# (and any comments you want to add after a '#')
# If you use DOS-style suffixes, you may want to uncomment the following:
#.cmd 01;32 # executables (bright green)
#.exe 01;32
#.com 01;32
#.btm 01;32
#.bat 01;32
# Or if you want to colorize scripts even if they do not have the
# executable bit actually set.
#.sh 01;32
#.csh 01;32
 # archives or compressed (bright red)
.tar 01;31
.tgz 01;31
.arc 01;31
.arj 01;31
.taz 01;31
.lha 01;31
.lz4 01;31
.lzh 01;31
.lzma 01;31
... etc
 

舉例分析
DIR 01;34 # directory
定義了目錄檔案使用 34 編碼， 在標準終端中， 顯示顏色是藍色

現在想要目錄在xshell中的顯示為綠色，由於目錄顏色為34編碼，對應第5個色塊（30對應第一個色塊）， 則在ASNI設定中點選 第一行第五個色塊， 在色板中選中綠色， 那麼目錄檔案將顯示為綠色。

假如出現了例外，執行 dircolors -p 顯示 DIR 01;35 # directory 那麼目錄的ASNI顏色是35 ， 則想要修改目錄的顯示顏色，則需要點 第一行第六個色塊。

到這裡終於可以明明白白的修改顏色顯示了。

dircolors 命令實際操作的是環境變數 $LS_COLORS

下面是一個指令碼檔案，列印顯示所有已定義的顏色規則

#!/bin/bash
# For LS_COLORS, print type and description in the relevant color.

IFS=:
for ls_color in $LS_COLORS; do
    color="${ls_color#*=}"
    type="${ls_color%=*}"

    # Add descriptions for named types.
    case "$type" in
    bd) type+=" (block device)" ;;
    ca) type+=" (file with capability)" ;;
    cd) type+=" (character device)" ;;
    di) type+=" (directory)" ;;
    do) type+=" (door)" ;;
    ex) type+=" (executable file)" ;;
    fi) type+=" (regular file)" ;;
    ln) type+=" (symbolic link)" ;;
    mh) type+=" (multi-hardlink)" ;;
    mi) type+=" (missing file)" ;;
    no) type+=" (normal non-filename text)" ;;
    or) type+=" (orphan symlink)" ;;
    ow) type+=" (other-writable directory)" ;;
    pi) type+=" (named pipe, AKA FIFO)" ;;
    rs) type+=" (reset to no color)" ;;
    sg) type+=" (set-group-ID)" ;;
    so) type+=" (socket)" ;;
    st) type+=" (sticky directory)" ;;
    su) type+=" (set-user-ID)" ;;
    tw) type+=" (sticky and other-writable directory)" ;;
    esac

    # Separate each color with a newline.
    if [[ $color_prev ]] && [[ $color != $color_prev ]]; then
        echo
    fi

    printf "\e[%sm%s\e[m " "$color" "$type"

    # For next loop
    color_prev="$color"
done
echo

執行這個指令碼，可以看到不同型別的檔案的顯示效果不同。

參考連結 http://www.cnblogs.com/xlmeng1988/archive/2013/01/08/shell_color.html
http://blog.chinaunix.net/uid-26021340-id-3481924.html
https://askubuntu.com/questions/17299/what-do-the-different-colors-mean-in-ls