## 系统层面
/etc/profile
/etc/bashrc
## 用户层面（用户目录下）
.bash_profile
.bashrc
.cshrc (csh)
即刻生效
```
source .bashrc
```
## 当前会话
bash
```
export h=Hello
export h="$h World"
export h="$h@2019"
export h="${h}August"
echo $h
```
csh
```
setenv h Hello
setenv h "$h World"
setenv h "$h@2019"
setenv h "${h}August"
echo $h
```
建议.bash_profile
```
if [ -f ~/.bashrc ]; then
source ~/.bashrc
fi
```
## -bash-4.2$
cd /etc/skel
cp .bash_logout .bash_profile .bashrc ~/
