在文件中查找一行，然后在bash中向该行的末尾添加一些内容 [英] Find a line in a file and add something to the end of the line in bash

问题描述

如何识别以特殊模式开头的行，并在行末添加内容?

如果应该添加的模式尚未附加

if the pattern that should be added is not already appended

假设我想通过开头的模式可能是ip地址或该行上方的注释来找到主机文件中的特定行

Let's say I'd like to find a specific line in the host file either by the pattern at the beginning may be an ip-address or by the comment that is above the line

一个例子可能是:

#This is your hosts file

127.0.0.1 localhost linux 

#This is added automatically 

192.168.1.2 domain1. com 

#this is added automatically to 

192.168.1.2 sub.domain1.com www.domain1.com

当您找到我告诉您的IP时，如何告诉bash.滚到行尾并添加一些东西

How do I tell bash when you find the IP I tell you. go ro the lines end and add something

或其他情况

当bash找到注释#This is added automatically

向下移动2，然后移至行尾并添加一些内容

go down by 2 and than go to the end of the line and add something

您看到我是一个初学者，没有任何想法在这里使用什么以及如何使用.是由sed完成的吗?还是可以用grep做到这一点?我必须为这些东西学习AWK吗?

You see I'm a beginner and don't have any Idea what to use here and how. Is dis done by sed? or could this be done with grep? do I have to learn AWK for that stuff?

推荐答案

给出以下内容:

文本文件:

[root@yourserver ~]# cat text.log 
#This is your hosts file

127.0.0.1 localhost linux 
[root@yourserver ~]# 

bash脚本:

[root@yourserver ~]# cat so.sh 
#!/bin/bash

_IP_TO_FIND="$1"

# sysadmin 101 - the sed command below will backup the file just in case you need to revert

_BEST_PATH_LINE_NUMBER=$(grep -n "${_IP_TO_FIND}" text.log | head -1 | cut -d: -f1)
_LINE_TO_EDIT=$(($_BEST_PATH_LINE_NUMBER+2))
_TOTAL_LINES=$( wc -l text.log)
if [[ $_LINE_TO_EDIT -gte $_TOTAL_LINES ]]; then
   # if the line we want to add this to is greater than the size of the file, append it
  sed -i .bak "a\${_LINE_TO_EDIT}i#This is added automatically\n\n192.168.1.2 domain1. com" text.log
else
  # else insert it directly 
  sed -i .bak "${_LINE_TO_EDIT}i\#This is added automatically\n\n192.168.1.2 domain1. com" text.log
fi

用法:

bash ./so.sh 127.0.0.1

只需输入您要查找的IP地址，此脚本在首次出现时便会匹配.

Simply enter in the ip address you're trying to find and this script matches on the first occurrence of it.

希望这会有所帮助！

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