个人学习笔记--sed命令（进阶篇）

深碍√TFBOYSˉ_ 2023-10-17 08:14 109阅读 0赞

删除所有空行
    [qs@qs ~]$ cat data1
    This is the header line.
    
    This is a data line.
    
    This is the last line.
    [qs@qs ~]$ sed '/^$/d' data1
    This is the header line.
    This is a data line.
    This is the last line.
    [qs@qs ~]$ 
    
    删除特定空行
    [qs@qs ~]$ sed '/header/{n;d}' data1
    This is the header line.
    This is a data line.
    
    This is the last line.
    [qs@qs ~]$ #n命令将会是得sed编辑器移动到模式匹配到的行的下一行。（“下一行”的数据将进入占据模式空间）
    
    -------
    
    [qs@qs ~]$ cat data2
    This is the header line.
    This is the first data line.
    This is the second data line.
    This is the last line.
    [qs@qs ~]$ sed '/first/{N;s/\n/ /}' data2 #合并行,将模式匹配到的行的下一行合并到模式匹配到的行。（“合并后的行”将占据模式空间）
    This is the header line.
    This is the first data line. This is the second data line.
    This is the last line.
    [qs@qs ~]$ 
    
    [qs@qs ~]$ sed '/first/{N}' data2 #虽然看起来是两行，但是sed编辑器会将它们看成是一行。
    This is the header line.
    This is the first data line.
    This is the second data line.
    This is the last line.
    
    [qs@qs ~]$ sed '/first/{N;d}' data2 #证明确实是一行。
    This is the header line.
    This is the last line.
    [qs@qs ~]$ 
    
    ------
    
    [qs@qs ~]$ cat data3
    The first meeting of the Linux System
    Administrator's group will be held on Tuesday.
    All System Administrators should attend this meeting.
    Thank you for your attendence.
    
    [qs@qs ~]$ sed 's/System Administrator/Desktop User/' data3 #错误匹配
    The first meeting of the Linux System #此处没有匹配到
    Administrator's group will be held on Tuesday.
    All Desktop Users should attend this meeting. #此处匹配成功
    Thank you for your attendence.
    [qs@qs ~]$ 
    
    [qs@qs ~]$ sed 'N; s/System.Administrator/Desktop User/' data3 #正确匹配之一（两行合并）
    The first meeting of the Linux Desktop User's group will be held on Tuesday.
    All Desktop Users should attend this meeting.
    Thank you for your attendence.
    [qs@qs ~]$ #System 和 Administrator 之间用了通配符来匹配空格和换行。
    
    [qs@qs ~]$ sed '
    > s/System Administrator/Desktop User/
    > N
    > s/System\nAdministrator/Desktop\nUser/
    > ' data3 #正确匹配之二（行不合并，保留原来格式） （注意区分这个和下面的错误示例）
    The first meeting of the Linux Desktop
    User's group will be held on Tuesday.
    All Desktop Users should attend this meeting.
    Thank you for your attendence.
    [qs@qs ~]$ 
    
    [qs@qs ~]$ sed '
    N
    s/System\nAdministrator/Desktop\nUser/
    s/System Administrator/Desktop User/
    ' data4 #错误示例
    The first meeting of the Linux Desktop
    User's group will be held on Tuesday.
    All System Administrators should attend this meeting.
    [qs@qs ~]$ 
    这个脚本总是在执行sed编辑器命令之前将下一行文本读入到模式空间。
    当读取到最后一行的时候，因为没有下一行，所以N命令就会让sed编辑器停止。
    
    -------
    多行删除命令
    
    [qs@qs ~]$ cat data4
    The first meeting of the Linux System
    Administrator's group will be held on Tuesday.
    All System Administrators should attend this meeting.
    [qs@qs ~]$ sed 'N; /System\nAdministrator/d' data4 #两行都被删除了
    All System Administrators should attend this meeting.
    [qs@qs ~]$ 
    
    [qs@qs ~]$ cat data4
    The first meeting of the Linux System
    Administrator's group will be held on Tuesday.
    All System Administrators should attend this meeting.
    [qs@qs ~]$ sed 'N; /System\nAdministrator/D' data4 #多行删除命令D，只删除模式空间的第一行。
    Administrator's group will be held on Tuesday.
    All System Administrators should attend this meeting.
    [qs@qs ~]$ 
    
    -----
    
    [qs@qs ~]$ cat data9 #第一行是空行
    
    This is the header line.
    This is a data line.
    
    This is the last line.
    [qs@qs ~]$ 
    [qs@qs ~]$ sed '/^$/{N; /header/D}' data9 #删除从中找到数据字符串的那行的前一行
    This is the header line.
    This is a data line.
    
    This is the last line.
    [qs@qs ~]$ 
    
    -------
    
    模式空间和保持空间
    
    [qs@qs ~]$ cat data2
    This is the header line.
    This is the first data line.
    This is the second data line.
    This is the last line.
    [qs@qs ~]$ sed -n '/first/{ #过滤含first的行
    > h #当含有first的行出现时，h命令将该行放到保持空间(This is the first data line.)
    > p #p命令打印模式空间也就是第一个数据行的内容
    > n #n命令提取数据流的下一行（This is the second data line.）, 并将它放到模式空间
    > p #p命令打印模式空间的内容，现在是第二个数据行(This is the second data line.)
    > g #g命令将保持空间的内容（This is the first data line.）放回模式空间，替换当前文本
    > p #p命令打印模式空间的内容（This is the first data line.）
    > }' data2
    This is the first data line.
    This is the second data line.
    This is the first data line.
    [qs@qs ~]$ 
    
    -------
    
    排除命令（！）
    [qs@qs ~]$ cat data2
    This is the header line.
    This is the first data line.
    This is the second data line.
    This is the last line.
    [qs@qs ~]$ sed -n '/header/!p' data2 #打印不包含header的行
    This is the first data line.
    This is the second data line.
    This is the last line.
    [qs@qs ~]$ 
    -------
    [qs@qs ~]$ cat data4
    The first meeting of the Linux System
    Administrator's group will be held on Tuesday.
    All System Administrators should attend this meeting. 
    
    [qs@qs ~]$ sed 'N; s/System.Administrator/Desktop User/' data4 #sed编辑器不处理数据流中最后一行文本，因为后面没有其他行了。
    The first meeting of the Linux Desktop User's group will be held on Tuesday.
    All System Administrators should attend this meeting.
    
    [qs@qs ~]$ sed '$!N; s/System.Administrator/Desktop User/' data4 #最后一行的时候没有执行N命令，其他的都执行了。
    The first meeting of the Linux Desktop User's group will be held on Tuesday.
    All Desktop Users should attend this meeting.
    [qs@qs ~]$ 
    -------
    [qs@qs ~]$ cat data2
    This is the header line.
    This is the first data line.
    This is the second data line.
    This is the last line.
    [qs@qs ~]$ 
    [qs@qs ~]$ sed -n '{
       1!G; h; $p}' data2 #翻转文本内容
    This is the last line.
    This is the second data line.
    This is the first data line.
    This is the header line.
    [qs@qs ~]$ 
    -------
    [qs@qs ~]$ sed 'G' data2 #加倍行间距（最后一行也加了空行）
    This is the header line.
    
    This is the first data line.
    
    This is the second data line.
    
    This is the last line.
    
    [qs@qs ~]$ 
    -------
    [qs@qs ~]$ sed '$!G' data2 #最后一行后面不加空行
    This is the header line.
    
    This is the first data line.
    
    This is the second data line.
    
    This is the last line.
    [qs@qs ~]$ 
    -------
    [qs@qs ~]$ cat data9
    
    This is the header line.
    This is a data line.
    
    This is the last line.
    [qs@qs ~]$ 
    [qs@qs ~]$ sed '/./,$!d' data9 #删除开头的空白行
    This is the header line.
    This is a data line.
    
    This is the last line.
    [qs@qs ~]$ 
    -------
    [qs@qs ~]$ cat data10
    This is the first line.
    
    This is the second line.
    
    This is the third line.
    
    
    This is the forth line.
    [qs@qs ~]$ sed '/./,/^$/!d' data10 #删除连续的空白行
    This is the first line.
    
    This is the second line.
    
    This is the third line.
    
    This is the forth line.
    [qs@qs ~]$ 
    -------
    [qs@qs ~]$ sed '=' data2 | sed 'N; s/\n/ /' #给文件中的行编号
    1 This is the header line.
    2 This is the first data line.
    3 This is the second data line.
    4 This is the last line.
    [qs@qs ~]$