058 通过HISTCONTROL变量去除历史记录中的重复记录

上面将的例子中虽然可以去除重复的历史记录，但是条件是这些重复记录必须是连续出现的。要去除整个历史记录中所有的重复记录可以将HISTCONTROL 设置为erasedups：

# export HISTCONTROL=erasedups

# pwd

# service httpd stop

# history | tail -3
      38  pwd
      39  service httpd stop
      40  history | tail -3

# ls -ltr

# service httpd stop

# history | tail -6
      35  export HISTCONTROL=erasedups
      36  pwd
      37  history | tail -3
      38  ls –ltr
      39  service httpd stop
      40  history | tail -6

[Note: The previous service httpd stop after pwd got
erased]