internal_variables 内部变量

internal_variables 内部变量

RANDOM 随机数

随机字符串

# echo $RANDOM | md5sum | cut -c 1-8
024cbfdc

随机数字

# echo $RANDOM | cksum | cut -c 1-8
20613431

HISTTIMEFORMAT 历史命令格式

$ export HISTTIMEFORMAT='%F %T  '

      1  2013-06-09 10:40:12   cat /etc/issue
      2  2013-06-09 10:40:12   clear
      3  2013-06-09 10:40:12   find /etc -name *.conf
      4  2013-06-09 10:40:12   clear
      5  2013-06-09 10:40:12   history
      6  2013-06-09 10:40:12   PS1='e[1;35m[u@h w]$ e[m '
      7  2013-06-09 10:40:12   PS1="e[0;32m[[email protected] W]$ e[m "
      8  2013-06-09 10:40:12   PS1="[email protected]:w [j]$ "
      9  2013-06-09 10:40:12   ping google.com
     10  2013-06-09 10:40:12   echo $PS1

HISTCONTROL 控制

ignoredups 过滤重复

$ export HISTCONTROL=ignoredups

unset export 关闭定义

$ unset export HISTCONTROL