bash Script to replace words

Question

Looking to run a script on the server to look at a path of a file and replace a word whereas it matches in the div.

So need to replace _toself to viewers where author equals a certain email test@example.com

URL=/var/www/sever/temp/fhyw1 FILE=user.txt

<div class='entry'>
  <div class='pageurl'>temp/fhyw1</div>
  <div class='context'>text</div>
  <div class='subject'>testing</div>
  <div class='notetext'></div>
  <div class='signed'>USER</div>
  <div class='author'>test@example.com</div>
  <div class='color'>0</div>
  <div class='visibility'>shared</div>
  <div class='to'>_toself</div>
  <div class='num'>4</div>
</div>
<div class='entry'>
  <div class='pageurl'>temp/fhyw1</div>
  <div class='context'>text</div>
  <div class='subject'>testing</div>
  <div class='notetext'></div>
  <div class='signed'>USER</div>
  <div class='author'>user@example.com</div>
  <div class='color'>0</div>
  <div class='visibility'>shared</div>
  <div class='to'>_viewers</div>
  <div class='num'>4</div>
</div>

Answer 1

This sed solution might work for you:

 sed -e '/^<div class=.entry.>/,\_^</div>_{//!{H;d};\_^</div>_!{h;d};x;/author.>test@example.com/s/_toself/SUBSTITUTE TEXT/;p;x}' text_file

N.B. You will need to replace SUBSTITUE TEXT with the viewers,_viewers or whatever

The sed command allows all lines other than those between <div class=.entry.> and </dev>(. allows for single 'or double quotes ") to pass through unchanged. If the line begins with <div class=.entry.> it is copied to a register call the hold space (HS) and then the pattern space (PS) is deleted. All other lines are appended to the HS and then deleted accepting the line </div>. When this line appears the HS is swapped with the PS and if this multiline contains author.>test@example.com then SUBSTITUTE TEXT is substituted for _toself. The multiline is printed out regardless, then the PS replaces the HS and it in turn to printed out.

Answer 2

We have some text

$> cat ./text 
<div class='entry'>
  <div class='pageurl'>temp/fhyw1</div>
  <div class='context'>text</div>
  <div class='subject'>testing</div>
  <div class='notetext'></div>
  <div class='signed'>USER</div>
  <div class='author'>test@example.com</div>
  <div class='color'>0</div>
  <div class='visibility'>shared</div>
  <div class='to'>_toself</div>
  <div class='num'>4</div>
</div>
<div class='entry'>
  <div class='pageurl'>temp/fhyw1</div>
  <div class='context'>text</div>
  <div class='subject'>testing</div>
  <div class='notetext'></div>
  <div class='signed'>USER</div>
  <div class='author'>user@example.com</div>
  <div class='color'>0</div>
  <div class='visibility'>shared</div>
  <div class='to'>_viewers</div>
  <div class='num'>4</div>
</div>

And we need to replace _toself 'to' value with viewers, but only in divs, where 'author' equals a test@example.com

I think sed can helps you, but you should have some experience with it to formulate all condition with sed syntax.

So, we can read file in while loop, cut it into a div-blocks and change one value by another only if blocks 'authors' value is equal some email.

#!/bin/bash

mail="test@example.com"
to_value_old=_toself
to_value_new=viewers

while IFS= read -r line; do
    if [[ -z "$( echo "$line" | grep -o -P "^<\/div>$" )" ]]; then
        entry_block="${entry_block}${line}\n"
    else
        entry_block="${entry_block}</div>\n"
        entry_block="$( echo -e "${entry_block}" )"
        if [[ -n "$( echo "${entry_block}" | grep -P "\<div class=\'author\'\>${mail}\<\/div\>" )" ]]; then
            entry_block="$( echo "${entry_block}" | sed -r -e "s/<div\ class='to'>${to_value_old}<\/div>/<div\ class='to'>${to_value_new}<\/div>/"  )"
        fi
        echo "${entry_block}"
        entry_block=""
    fi
done < ./text

And we get

$> ./div.sh 
<div class='entry'>
  <div class='pageurl'>temp/fhyw1</div>
  <div class='context'>text</div>
  <div class='subject'>testing</div>
  <div class='notetext'></div>
  <div class='signed'>USER</div>
  <div class='author'>test@example.com</div>
  <div class='color'>0</div>
  <div class='visibility'>shared</div>
  <div class='to'>viewers</div>
  <div class='num'>4</div>
</div>
<div class='entry'>
  <div class='pageurl'>temp/fhyw1</div>
  <div class='context'>text</div>
  <div class='subject'>testing</div>
  <div class='notetext'></div>
  <div class='signed'>USER</div>
  <div class='author'>user@example.com</div>
  <div class='color'>0</div>
  <div class='visibility'>shared</div>
  <div class='to'>_viewers</div>
  <div class='num'>4</div>
</div>

Done.

Answer 3

If you only want to replace all occurrences of _toself by something else, then sed will do the job perfectly.

sed 's/_toself/replacement_string/'

If you want to do this only within the div with a specified author then it's a bit more tricky.