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Linux上文本处理三剑客sed用法

Linux上文本处理三剑客sed用法

作者: SRE1 | 来源:发表于2019-04-15 18:21 被阅读0次

文本处理三剑客:

grep, egrep, fgrep:文本过滤器
sed:Stream EDitor,流编辑器,行
awk:文本格式化工具,报告生成器

sed [OPTION]... 'script' [input-file] ...
script组成格式:
地址定界编辑命令

OPTION:

-n:不输出模式空间中的内容至屏幕
-e script, --expression=script:多点编辑
-f /PATH/TO/SED_SCRIPT_FILE
SED_SCRIPT:每行一个编辑命令
-r, --regexp-extended:支持使用扩展正则表达式
-i[SUFFIX], --in-place[=SUFFIX]:直接编辑原文件

[root@promote ~]# sed  -e  's@^#[[:space:]]*@@'   -e  '/^UUID/d'  /etc/fstab


/etc/fstab
Created by anaconda on Sun Apr 14 09:29:51 2019

Accessible filesystems, by reference, are maintained under '/dev/disk'
See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0
地址定界:

(1) 空地址:对全文进行处理;

(2) 单地址:
#:指定行;
/pattern/:被此模式所匹配到的每一行;

(3) 地址范围
#,#:
#,+#:
#,/pat1/
/pat1/,/pat2/
$:最后一行;

(4) 步进:~
1~2:所有奇数行
2~2:所有偶数行

编辑命令:

d:删除

[root@promote ~]# cat /etc/fstab 

#
# /etc/fstab
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0
[root@promote ~]# sed '/^#/d' /etc/fstab 

/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

p:显示模式空间中的内容

[root@promote ~]# sed  '2~2p' /etc/fstab   #偶数行会显示两遍

#
#
# /etc/fstab
# Created by anaconda on Sun Apr 14 09:29:51 2019
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0
[root@promote ~]# sed -n  '2~2p' /etc/fstab  #显示所有的偶数行
#
# Created by anaconda on Sun Apr 14 09:29:51 2019
# Accessible filesystems, by reference, are maintained under '/dev/disk'
#
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

a \text:在行后面追加文本“text”,支持使用\n实现多行追加

[root@promote ~]# sed '3a \new line' /etc/fstab 

#
# /etc/fstab
new line
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0
[root@promote ~]# sed '3a \new line\nanother new line' /etc/fstab 

#
# /etc/fstab
new line
another new line
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

i \text:在行前面插入文本“text”,支持使用\n实现多行插入

[root@promote ~]# sed '3i \new line' /etc/fstab 

#
new line
# /etc/fstab
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

c \text:把匹配到的行替换为此处指定的文本“text”

[root@promote ~]# sed '4c \change line' /etc/fstab 

#
# /etc/fstab
change line
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

w /PATH/TO/SOMEFILE:保存模式空间匹配到的行至指定的文件中

[root@promote ~]# sed -n '/^[^#]/p' /etc/fstab 
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0
[root@promote ~]# sed '/^[^#]/w /tmp/fstab.new' /etc/fstab 

#
# /etc/fstab
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0
[root@promote ~]# cat /tmp/fstab.new 
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

r /PATH/FROM/SOMEFILE:读取指定文件的内容至当前文件被模式匹配到的行后面;文件合并;

[root@promote ~]# sed '3r /etc/issue' /etc/fstab 

#
# /etc/fstab
\S
Kernel \r on an \m

# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

=:为模式匹配到的行打印行号

[root@promote ~]# sed '/^UUID/=' /etc/fstab 

#
# /etc/fstab
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
10
/dev/mapper/centos_promote-root /                       xfs     defaults        0 0
11
UUID=273deb66-d03c-457f-8b29-5df019b3e53a /boot                   xfs     defaults        0 0
/dev/mapper/centos_promote-home /home                   xfs     defaults        0 0
/dev/mapper/centos_promote-swap swap                    swap    defaults        0 0

!:条件取反
格式:地址定界!编辑命令

[root@promote ~]# sed '/^#/!d' /etc/fstab 
#
# /etc/fstab
# Created by anaconda on Sun Apr 14 09:29:51 2019
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#

s///:查找替换,其分隔符可自行指定,常用的有s@@@, s###等
替换标记:

g:全局替换
w /PATH/TO/SOMEFILE:将替换成功的结果保存至指定文件中
p:显示替换成功的行

练习1:删除/boot/grub/grub2.cfg文件中所有以空白字符开头的行的行首的所有空白字符;

[root@promote ~]# sed  's@^[[:space:]]\+@@' /etc/grub2.cfg

练习2:删除/etc/fstab文件中所有以#开头的行的行首的#号及#后面的所有空白字符;

[root@promote ~]# sed  's@^#[[:space:]]*@@'  /etc/fstab

练习3:输出一个绝对路径给sed命令,取出其目录,其行为类似于dirname;

[root@promote ~]# echo "/var/log/messages/" | sed 's@[^/]\+/\?$@@'
[root@promote ~]# echo "/var/log/messages" | sed -r 's@[^/]+/?$@@'

高级编辑命令:

h:把模式空间中的内容覆盖至保持空间中;
H:把模式空间中的内容追加至保持空间中;
g:把保持空间中的内容覆盖至模式空间中;
G:把保持空间中的内容追加至模式空间中;
x:把模式空间中的内容与保持空间中的内容互换;
n:覆盖读取匹配到的行的下一行至模式空间中;
N:追加读取匹配到的行的下一行至模式空间中;
d:删除模式空间中的行;
D:删除多行模式空间中的所有行;

示例:

sed -n 'n;p' FILE:显示偶数行;
sed '1!G;h;$!d' FILE:逆序显示文件的内容;
sed ’$!d' FILE:取出最后一行;
sed '$!N;$!D' FILE:取出文件后两行;
sed '/^$/d;G' FILE:删除原有的所有空白行,而后为所有的非空白行后添加一个空白行;
sed 'n;d' FILE:显示奇数行;
sed 'G' FILE:在原有的每行后方添加一个空白行;

练习:用bash实现统计访问日志文件中状态码大于等于400的IP数量并排序

[root@localhost ~]# cat nginx_access_log | cut -d' ' -f1,9 | grep '\<[4-9][0-9][0-9]\>' | cut -d' ' -f1 | sort | uniq -c | sort -r
      7 100.109.195.28
      4 100.109.195.26
      2 100.109.195.27

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