Shell Programming and Scripting

vDate=`echo $filename | rev | sed 's/.*\([0-9]\)\..*//g' | rev`

test.input.20130501010101.txt
test.input.crm.201405010202.dat

echo "test.input.20130501010101.txt" | awk 'gsub(/[[:alpha:]]/,X) gsub(/[[:punct:]]/,Y) 1'

20130501010101

vDate=`echo $filename | sed -n 's/.*\.\([0-9]\{1,\}\)\..*/\1/gp'`

vdate=${filename%.*}
vdate=${vdate##*[!0-9]}

vdate=$(echo "$filename" | awk -F. '{$0=$(NF-1)}/^[0-9]+$/')

echo test.input.20130501010101.txt | grep -o '[0-9]\{12,\}*'

vDate=`echo $filename | sed -n 's/.*\.\([0-9]\{1,\}\)\..*/\1/gp'`

echo $filename | rev | sed 's/.*\.\([0-9]\{1,\}\)\..*/\1/g' | rev

$ filename=test.input.20130501010101.txt
$ echo $filename | rev | sed 's/.*\([0-9]\)\..*/\1/g' | rev
2
$ echo $filename | rev | sed 's/.*\([0-9]\{1,\}\)\..*/\1/g' | rev
2
$ echo $filename | rev | sed 's/.*\.\([0-9]\{1,\}\)\..*/\1/g' | rev
20130501010101