SED replace string inside a string

Try

replacementLine=$(echo ${originalLine} | sed -E 's/('${escParamToChange}'=)"[^"]+"/\1"'${value}'"/')

• \1 replaces captured group ('${escParamToChange}'=) (shortcut)
• "[^"]+" matches the value starting with ", followed by one or more non-"-characters, followed by closing "

Works on "sed (GNU sed) 4.4"

$ originalLine='<com.whatsapp.voipcalling.VideoCallParticipantViewLayout android:id="@id/video_participant_views" android:layout_width="fill_parent" android:layout_height="fill_parent"/>'
$ value="10dip"
$ for escParamToChange in android:layout_width android:layout_height; do echo ${originalLine} | sed -E 's/('${escParamToChange}'=)"[^"]+"/\1"'${value}'"/'; done
<com.whatsapp.voipcalling.VideoCallParticipantViewLayout android:id="@id/video_participant_views" android:layout_width="10dip" android:layout_height="fill_parent"/>
<com.whatsapp.voipcalling.VideoCallParticipantViewLayout android:id="@id/video_participant_views" android:layout_width="fill_parent" android:layout_height="10dip"/>

As you found, this command removes too much:

$ echo "${originalLine}" | sed -E 's/'${escParamToChange}'=[^ ]*/'${escParamToChange}'="'${value}'"/'
<com.whatsapp.voipcalling.VideoCallParticipantViewLayout android:id="@id/video_participant_views" android:layout_width="fill_parent" android:layout_height="10dip"

This command, however, works:

$ echo "${originalLine}" | sed -E 's/'${escParamToChange}'=[^ /]*/'${escParamToChange}'="'${value}'"/'
<com.whatsapp.voipcalling.VideoCallParticipantViewLayout android:id="@id/video_participant_views" android:layout_width="fill_parent" android:layout_height="10dip"/>

The problem was that [^ ]* matches the />. If we replace [^ ]* with [^ /], then the /> is excluded from the match.

A potential problem with the above is that ${escParamToChange} and ${value} appear on the command line unquoted. If they were to contain spaces or other shell-active characters, this would lead to unwanted results.

Alternative: Using awk

Awk has the advantage of handling variables in a sensible way and this avoids some potential pitfalls that occur when trying to stuff shell variables into sed commands. It also, in my opinion, simplifies the quoting issues:

$ echo "${originalLine}" | awk -v regex="${escParamToChange}=[^ /]*" -v new="${escParamToChange}=\"${value}\"" '{gsub(regex, new)} 1'
<com.whatsapp.voipcalling.VideoCallParticipantViewLayout android:id="@id/video_participant_views" android:layout_width="fill_parent" android:layout_height="10dip"/>

Using xq, an XML-aware editing tool from https://kislyuk.github.io/yq/, to modify the attribute:

replacementLine=$( printf '%s\n' "$originalLine" |
        xq -x \
                --arg attrib "@$escParamToChange" \
                --arg value "$value" \
                '(.[] | .[$attrib]) |= $value' )

printf '%s\n' "$replacementLine"

This imports the name of the attribute to change in the internal variable attrib, and the value to change it to in value. The path expression .[] | .[$attrib] expands to all attributes with to name of the attribute that we'd like to change (note that the attribute name is prefixed with @ on the command line, which designates it as an attribute and not as a sub-node).