bash用特定索引替换文件中的字符串

Question

I have 2 files:

idfile.txt :

1111
3333

replace.xml :

<condition="online" id="1111" >
<condition="online" id="2222" >
<condition="online" id="3333" >
<condition="online" id="4444" >

I need a script to get below output.xml :

<condition="offline" id="1111" >
<condition="online" id="2222" >
<condition="offline" id="3333" >
<condition="online" id="4444" >

I use:

while read line; do
grep $line replace.xml | sed 's/condition="online"/condition="offline"/g' replace.xml >> output.xml 
done < idfile.txt

My script replace all condition="online" in condition="offline" .

Thanks a lot!

Answer 1

Note, id attribute value from replace.xml should match any of the entries from idfile.txt to fit the condition.

Awk + paste solution:

awk -v ids="$(paste -s -d'|' idfile.txt)" 'match($2,ids){ sub("online","offline",$1) }1' replace.xml

The output:

<condition="offline" id="1111" >
<condition="online" id="2222" >
<condition="offline" id="3333" >
<condition="offline" id="4444" >

Answer 2

If your files are going to be large, I would use awk . Please note that your idfile.txt should be:

1111
3333

To get something interesting.

This is how I would do it with awk :

#!/bin/bash

awk '
  BEGIN {
    while( (getline $l < "idfile.txt") > 0 ) {
      if( $l ~ /^.+$/ ) {
        id[$l] = 1;
      }
    }
    close("idfile.txt");
  }

  /^.+$/ {
    split($2, a, "\"");
    if( id[ a[2] ] ) {
      printf "<condition=\"online\" id=\"%s\">\n", a[2];
    }
    else {
      printf "<condition=\"offline\" id=\"%s\">\n", a[2];
    }
  }
' replace.xml >output.xml

The BEGIN block reads the id file to the id array. awk uses a hash to implement lookups so they are efficient. The regular expressions /^.+$/ are meant to avoid processing empty lines. The code is meant to be contained in a bash (text) file.

$2 will get the pieces id="nnnn"> and the split will get in array a[2] the part of that within the quotes.

Answer 3

awk one liner

$ awk 'FNR==NR{a[$0]; next} ($4 in a){gsub(/online/,"offline")}1' idfile.txt FS='"' replace.xml

First : Store all id's in a
Next , while iterating over replace.xml, if id ie $4 exists in array a then replace online with offline . Note: Field separator is " for replace.xml

Output

<condition="offline" id="1111" >
<condition="online" id="2222" >
<condition="offline" id="3333" >
<condition="online" id="4444" >