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copied!<p>Since it bugged me a lot I have asked directly on www.unix.com and was kindly provided with a solution which fits for my ancient shell. So if anyone got the same problem here is the solution:</p> <pre><code>line='aaaa$aa{yyy}aaa${important}xxxxxxxx${important2}oo{o$}oo$oo${importantstring3}' IFS=\$ read -a words <<< "$line" regex='^(\{[^}]+})' for e in "${words[@]}"; do if [[ $e =~ $regex ]]; then echo "\$${BASH_REMATCH[0]}"; fi; done </code></pre> <p>which prints then the following - without even getting disturbed by random occurrences of <code>$</code> and <code>{</code> or <code>}</code> between the syntactically correct expressions:</p> <pre><code>${important} ${important2} ${importantstring3} </code></pre> <p>I have updated the full solution after I got another update from the forums: now it also ignores this: <code>aaa$aa{yyy}aaaa</code> - which it previously printed as ${yyy} - but which it should completely ignore as there are characters between <code>$</code> and <code>{</code>. Now with the additional anchoring on the beginning of the regexp it works as expected.</p> <p>I just found another issue: theoretically using the above approach I would still get a wrong output if the read line looks like this <code>line='{ccc}aaaa${important}aaa'</code>. The IFS would split it and the REGEX would match <code>{ccc}</code> although this hadn't the <code>$</code> sign in front. This is suboptimal.<br> However following approach could solve it: after getting the BASH_REMATCH I would need to do a search in the original line - the one I gave to the IFS - for this exact expression <code>${ccc}</code> - with the difference, that the <code>$</code> is included! And only if it finds this exact match, only then, it counts as a valid match; otherwise it should be ignored. Kind of a reverse search method...<br></p> <p>Updated - add this reverse search to ignore the trap on the beginning of the line:</p> <pre><code>pattern="\$${BASH_REMATCH[0]}"; searchresult=""; searchresult=`echo "$line" | grep "$pattern"`; if [ "$searchresult" != "" ]; then echo "It was found!"; fi; </code></pre> <p>Neglectable issue: If the line looks like this <code>line='{ccc}aaaaaa${ccc}bbbbb'</code> it would recognize the <em>first</em> <code>{ccc}</code> as a valid match (although it isn't) and print it, because the reverse search found the <em>second</em> <code>${ccc}</code>. Although this is not intended it's irrelevant for my specific purpose as it implies that this pattern does in fact exist at least once in the same line.</p>

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