Truncate the content within alt attribute to first 250 characters.

Shell Programming and Scripting
1

I have a xml file which contains image tag as follows:

<image><img src="wstc_0007_0007_0_img0001.jpg" width="351" height="450" alt="This is the cover page. Brazil � Japan � Korea � Mexico � Singapore � Spain" type="photograph" orient="portrait"/></image>

Now, i want to write a script that will count whether the number of characters within alt attribute are greater than 250 and if it is; the data within alt attribute should be truncated to contain only first 250 characters.

It would be really nice if anybody could provide me the way to do so.

2

You know, if it truncated it in the middle of an � or somesuch the result could be invalid HTML.

3

This truncates the alt attribute by item, rather than characters:

altcheck() #@ USAGE: altcheck [max]
{ #@ Truncate the alt attribute in $line to $max characters
  max=${1:-250}
  right=${line#*alt=\"}
  left=${line%"$right"}
  alt=${right%%\"*}
  right=${line#*"$alt"}
  while [ ${#alt} -gt $max ]
  do
    alt=${alt% &*}
  done
  line=$left$alt$right
}

while IFS= read -r line
do
  case $line in
    *"<img"*alt=*) altcheck ;;
  esac
  printf "%s\n" "$line"
done < "$FILE"
4

Hi Johnson!

Thanks for your help! . But above script is not working. Please help!!!. Thanks.

5

I duplicated some of the text inside that alt area so I could show it trimmed down. And then trimmed it at 150.
Note that it does not necessarily break nicely, and does not address the quotation " character.
However, this logic appears to trim on that field.

> cat file164
<image><img src="wstc_0007_0007_0_img0001.jpg" width="351" height="450" alt="This is the cover page. Brazil � Japan � Korea � Mexico � Singapore � Spain" type="photograph" orient="portrait"/></image>
<image><img src="wstc_0007_0007_0_img0001.jpg" width="351" height="450" alt="This is the cover page. Brazil � Japan � Korea � Mexico � Singapore � Spain Brazil � Japan � Korea � Mexico � Singapore � Spain" type="photograph" orient="portrait"/></image>

> sed "s/alt/~alt/g" file164 | sed "s/type/~type/g" | awk -F"~" '{print $1,substr($2,1,150),$3}'
<image><img src="wstc_0007_0007_0_img0001.jpg" width="351" height="450"  alt="This is the cover page. Brazil � Japan � Korea � Mexico � Singapore � Spain"  type="photograph" orient="portrait"/></image>
<image><img src="wstc_0007_0007_0_img0001.jpg" width="351" height="450"  alt="This is the cover page. Brazil � Japan � Korea � Mexico � Singapore � Spain Brazil � Japan � Kor type="photograph" orient="portrait"/></image>
6

What does "not working" mean? What does happen?

Where does the script fail?

Are there any error messages?