To get all the lines from a slurped input file to show up as a single line on output, you want something like this:

perl -e 'undef $/; $_=<>; tr/\n/ /; s/ $/\n/; print'  list
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Or you could just use unix/linux commands that do the same thing:

xargs echo -n < list
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(If you want a clean line break at the end of that output, add  && echo at the end.)