ll命令其实就是ls -l，当然如果想显示隐藏信息就是 ls -al。

我个人是特别喜欢ll代替ls -al命令，并且还要有颜色的那种。

今天卸载软件重新安装环境变量怎么都不对了，一生气把环境变量都清空了。命令：unset PATH

然后就手动添加环境变量：

/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/root/bin

但是ll命令却没有了。

解决方案一 （没有颜色）：

在~/.bashrc文件最上面添加

alias ll='ls -la' #这一行是让命令行支持llalias ls="ls --color" #这一行是让ls有颜色

然后运行命令：source ~/.bashrc

此时ll就有了，并且重新打开终端也生效

解决方案二：

从另一台机器上复制了一份/etc/profile文件过来发现就有颜色了。可能是我之前的/etc/profile文件坏了。

centos7文件内容如下，其他系统不清楚是否一样：

网盘链接：

链接: https://pan.baidu.com/s/1iqDphAxqxxTuB-H75LRpGA 提取码: zzp2 

# /etc/profile# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc# It's NOT a good idea to change this file unless you know what you
# are doing. It's much better to create a custom.sh shell script in
# /etc/profile.d/ to make custom changes to your environment, as this
# will prevent the need for merging in future updates.pathmunge () {case ":${PATH}:" in*:"$1":*);;*)if [ "$2" = "after" ] ; thenPATH=$PATH:$1elsePATH=$1:$PATHfiesac
}if [ -x /usr/bin/id ]; thenif [ -z "$EUID" ]; then# ksh workaroundEUID=`/usr/bin/id -u`UID=`/usr/bin/id -ru`fiUSER="`/usr/bin/id -un`"LOGNAME=$USERMAIL="/var/spool/mail/$USER"
fi# Path manipulation
if [ "$EUID" = "0" ]; thenpathmunge /usr/sbinpathmunge /usr/local/sbin
elsepathmunge /usr/local/sbin afterpathmunge /usr/sbin after
fiHOSTNAME=`/usr/bin/hostname 2>/dev/null`
HISTSIZE=1000
if [ "$HISTCONTROL" = "ignorespace" ] ; thenexport HISTCONTROL=ignoreboth
elseexport HISTCONTROL=ignoredups
fiexport PATH USER LOGNAME MAIL HOSTNAME HISTSIZE HISTCONTROL# By default, we want umask to get set. This sets it for login shell
# Current threshold for system reserved uid/gids is 200
# You could check uidgid reservation validity in
# /usr/share/doc/setup-*/uidgid file
if [ $UID -gt 199 ] && [ "`/usr/bin/id -gn`" = "`/usr/bin/id -un`" ]; thenumask 002
elseumask 022
fifor i in /etc/profile.d/*.sh /etc/profile.d/sh.local ; doif [ -r "$i" ]; thenif [ "${-#*i}" != "$-" ]; then . "$i"else. "$i" >/dev/nullfifi
doneunset i
unset -f pathmunge

千万不要放在windows系统里编辑这个文档，linux和windows编码方式不同，我就在windows下打个空格然后就报错：

-bash: $'\r': command not found
用上述文件替换自己的/etc/profile

执行命令：source /etc/profile

好了，现在所有的终端打开都可以使用ll并且是有颜色的了: