Pad valores numéricos no nome do arquivo com três dígitos usando sed

Estou passando um nome de arquivo para o meu script bash e limpando o nome usando sed. Alguns arquivos de exemplo seriam:

Test 01.txt
Test v2 01.txt

Gostaria de voltar:

Test 001.txt
Test v002 001.txt

Aqui está o meu script

#!/bin/bash

SAVEIFS=$IFS
IFS=$(echo -en "\n\b")
for f in $@
do

j=`basename "$f" ".???"`
BASENAME=`basename "$f" ".???"`
DIRNAME=`dirname "$f"`

j=`echo $j |sed -e 's/\///g'`
j=`echo $j |sed -e 's/_/ /g'`
j=`echo $j |sed -e 's/^\.//'`
j=`echo $j |sed -e 's/\[[^()]*\]//g'`
j=`echo $j |sed -e 's/([^()]*)//g'`
j=`echo $j |sed -e 's/#//g'`
j=`echo $j |sed -e 's/+/\ /g'`
j=`echo $j |sed -e 's/\.\././g'`
j=`echo $j |sed -e 's/\&/and/g'`
j=`echo $j |sed -e 's/\ -/-/g'`
j=`echo $j |sed -e 's/-\ /-/g'`
j=`echo $j |sed -e 's/-{2,}/-/g'`
j=`echo $j |sed -r -e 's/\d+/sprintf("%03d",
#!/bin/bash

SAVEIFS=$IFS
IFS=$(echo -en "\n\b")
for f in $@
do

j=`basename "$f" ".???"`
BASENAME=`basename "$f" ".???"`
DIRNAME=`dirname "$f"`

j=`echo $j |sed -e 's/\///g'`
j=`echo $j |sed -e 's/_/ /g'`
j=`echo $j |sed -e 's/^\.//'`
j=`echo $j |sed -e 's/\[[^()]*\]//g'`
j=`echo $j |sed -e 's/([^()]*)//g'`
j=`echo $j |sed -e 's/#//g'`
j=`echo $j |sed -e 's/+/\ /g'`
j=`echo $j |sed -e 's/\.\././g'`
j=`echo $j |sed -e 's/\&/and/g'`
j=`echo $j |sed -e 's/\ -/-/g'`
j=`echo $j |sed -e 's/-\ /-/g'`
j=`echo $j |sed -e 's/-{2,}/-/g'`
j=`echo $j |sed -r -e 's/\d+/sprintf("%03d",$&)/e'`
j=`echo $j |sed -e 's/\.\././g'`
j=`echo $j |sed -e "s/\'//g"`
j=`echo $j |sed -r -e 's/ {2,}/ /g'`
j=`echo $j |sed -e 's/\ \././g'`

if [ "$BASENAME" != "$j" ]; then
  mv -v "$f" "$DIRNAME"/"$j"
fi

done
amp;)/e'` j=`echo $j |sed -e 's/\.\././g'` j=`echo $j |sed -e "s/\'//g"` j=`echo $j |sed -r -e 's/ {2,}/ /g'` j=`echo $j |sed -e 's/\ \././g'` if [ "$BASENAME" != "$j" ]; then mv -v "$f" "$DIRNAME"/"$j" fi done

Aqui está a linha do problema

j=`echo $j |sed -r -e 's/\d+/sprintf("%03d",
j=`echo $j |sed -r -e 's/\d+/sprintf("%03d",$&)/e'`
amp;)/e'`

O regex funcionará com renomeação, mas não com se

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