Time use of xargs and awk to rename a set of directories

awk-versus-xargs

#!/usr/bin/env bash

set -e
((DEBUG)) && set -x

TIMES=100
WORDS=100
rm -rf $(<head-words)
rm -rf $(<tail-words)
uniq -i /usr/share/dict/words > uniq-words
tail -$WORDS uniq-words > tail-words
head -$WORDS uniq-words > head-words
paste -d' ' head-words tail-words > paired-words

for c in 'cat paired-words | xargs -n2 mv' \
         '< paired-words xargs -n2 mv' \
         "awk '{system(\"mv \" \$1 \" \" \$2)}' paired-words"
do
  echo "Executing $TIMES trials of \`$c\`"
  time for n in $(seq 1 $TIMES)
  do
      mkdir $(<head-words)
      sh -c "$c"
      rmdir $(<tail-words)
  done
  echo
done