C:\>perl -le"$_=shift; s/\b(\w)(\w*)(\w)\b/$3$2$1/g;print"  "12345 AbcD"
52341 DbcA

C:\>perl -le"$_=shift; s/\b(\w)(\w*)(\w)\b/$3$2$1/g;print"  "12345
52341

C:\>perl -le"$_=shift; s/\b(\w)(\w*)(\w)\b/$3$2$1/g;print"  "AbcD
DbcA

C:\>perl -le"$_=shift; s/\b(\w)(\w*)(\w)\b/$3$2$1/g;print"  "AbcD 12345"
DbcA 52341

C:\>