Complicated variable content failed to get into sed

Question

The first line is variable ann hold quite complicated value. The reason I use the second line is because I don't want to change anything in the third line col1content. To change replacement, I just need to change second line to other variable.

ann="<?php echo '<h2>'.views_get_view('frprev_ann')->get_title().'<\/h2>'; echo views_embed_view('frprev_ann'); ?>"
col1content=`echo $ann`
sed -i 's/r'$rownum'c1content/'$col1content'/g' templates/page--front.tpl.php

But when above command has been run, it result in error:

sed: -e expression #1, char 19: unterminated `s' command

If I change the first line to be ann="testtext", everything running smoothly. And when change first line to be ann="<?first second", it fails. using backslash also cannot help me.

Answer 1

sed -i 's/r'$rownum'c1content/'"$col1content"'/g' templates/page--front.tpl.php

Answer 2

You can't reliably pass text to sed like this. In the replacement text, you need to quote \, & and the s delimiter (usually /) by adding a backslash before them. In the regex part, you need to quote \[.*^$ and the delimiter.

In addition, you've left the value of the variable to be further expanded by the shell. Always use double quotes around variable substitutions, i.e. "$foo", not $foo. Without double quotes, the value is interpreted as a whitespace-delimited list of glob patterns; whitespace and \[?* are expanded.

If you don't want to change the way the script works, quote everything properly:

ann="<?php echo '<h2>'.views_get_view('frprev_ann')->get_title().'</h2>'; echo views_embed_view('frprev_ann'); ?>"
col1content=$(echo "$ann" | sed 's/[\\\/&]/\\&/g')
sed -i "s/r${rownum}c1content/${col1content}/g" templates/page--front.tpl.php

Alternatively, use awk or perl, which can read an environment variable from within the script.

ann="<?php echo '<h2>'.views_get_view('frprev_ann')->get_title().'</h2>'; echo views_embed_view('frprev_ann'); ?>"
awk -v ann="$ann" -v rownum="$rownum" '
    BEGIN {pattern = "r" rownum "c1content"; }
    1 {gsub(pattern, ann); print}
' templates/page--front.tpl.php >templates/page--front.tpl.php.new
mv templates/page--front.tpl.php.new templates/page--front.tpl