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  • linux系统中如何删除空行

    linux系统中如何删除空行。

    1、测试数据 a.txt

    [root@centos79 test]# ls
    a.txt
    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# cat -A a.txt
    a g r e$
    $                ## 空行什么也没有
    i x k like$
    a f g liker$
    [root@centos79 test]# sed -n l a.txt
    a g r e$
    $                    ## 空行什么也没有
    i x k like$
    a f g liker$

    2、删除空行

    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# grep -v "^$" a.txt
    a g r e
    i x k like
    a f g liker
    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# sed '/^$/d' a.txt
    a g r e
    i x k like
    a f g liker
    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# awk '/./{print}' a.txt
    a g r e
    i x k like
    a f g liker

    继续

    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# awk NF a.txt
    a g r e
    i x k like
    a f g liker
    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# sed '/^s*$/d' a.txt
    a g r e
    i x k like
    a f g liker
    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# sed '/^[	 ]*$/d' a.txt
    a g r e
    i x k like
    a f g liker

    3、修改测试文件,在空行中添加空格或者水平制表符

    修改后的测试文件:

    [root@centos79 test]# ls
    a.txt
    [root@centos79 test]# cat a.txt
    
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# cat -A a.txt
    $
    a g r e$
      $
    i x k like$
    ^I^I$
    a f g liker$
    [root@centos79 test]# sed -n l a.txt
    $
    a g r e$
      $
    i x k like$
    		$
    a f g liker$

    4、进行测试

    [root@centos79 test]# ls
    a.txt
    [root@centos79 test]# cat a.txt
    
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# grep -v "^$" a.txt
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# cat a.txt
    
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# sed '/^$/d' a.txt
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# cat a.txt
    
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# awk '/./{print}' a.txt
    a g r e
    
    i x k like
    
    a f g liker

    继续

    [root@centos79 test]#  ls
    a.txt
    [root@centos79 test]# cat a.txt
    
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# awk NF a.txt
    a g r e
    i x k like
    a f g liker
    [root@centos79 test]# cat a.txt
    
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# sed '/^s*$/d' a.txt
    a g r e
    i x k like
    a f g liker
    [root@centos79 test]# cat a.txt
    
    a g r e
    
    i x k like
    
    a f g liker
    [root@centos79 test]# sed '/^[	 ]*$/d' a.txt
    a g r e
    i x k like
    a f g liker

    5、补充

    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# cat -A a.txt
    a g r e$
    $
    i x k like$
    a f g liker$
    [root@centos79 test]# awk '$0 != ""' a.txt
    a g r e
    i x k like
    a f g liker

    6、补充

    [root@centos79 test]# ls
    a.txt
    [root@centos79 test]# cat a.txt
    a g r e
    
    i x k like
    a f g liker
    [root@centos79 test]# cat -A a.txt
    a g r e$
    $
    i x k like$
    a f g liker$
    [root@centos79 test]# cat a.txt |tr -s "
    "
    a g r e
    i x k like
    a f g liker
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  • 原文地址:https://www.cnblogs.com/liujiaxin2018/p/14969792.html
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