ファイル名の先頭に一括して文字列を追加する

#!/bin/sh
#add_prefix.sh

. f_askdir.sh
. f_askstring.sh

ask_directory 1
if [ $? -eq 1 ]; then
    return 1
fi
echo "Target directory is \"${_DIRNAME}\""

ask_string "Input Common Filename(Blank is 0mission): " 1
COMNAME=$_STR
if [ ! "$COMNAME" ]; then
    echo "Omit Common Filename."
else
    echo "Common Filename is \"${COMNAME}\""
fi

ask_string "Input Target Extension(Blank is Omission): " 1
EXTENSION=$_STR
if [ ! "$EXTENSION" ]; then
    echo "Omit Extension."
else
    echo "Extension is \"${EXTENSION}\""
fi

ask_string "Input prefix: " 0
PREFIX=$_STR
echo "Prefix is \"${PREFIX}\""

#置換条件
#ディレクトリのみ指定
if [ ! "$COMNAME" -a ! "$EXTENSION" ]; then
    SERCHNAME=*
#拡張子省略
elif [ "$COMNAME" -a ! "$EXTENSION" ]; then
    SERCHNAME=$COMNAME*.*
#共通部分省略
elif [ ! "$COMNAME" -a "$EXTENSION" ]; then
    SERCHNAME=*.$EXTENSION
else
    SERCHNAME=$COMNAME*.$EXTENSION
fi
echo $SERCHNAME
CURRENDIR=$(pwd)
cd $_DIRNAME

NUM=0
for FNAME in $SERCHNAME; do
    if [ -f "$FNAME" ]; then
        mv $FNAME $PREFIX$FNAME
        NUM=$(expr $NUM + 1)
    fi
done
if [ $NUM -eq 0 ]; then
    echo "No file."
else
    echo "*** Successful."
fi
cd $CURRENTDIR
unset _DIRNAME COMNAME EXTENSION SERCHNAME CURRENTDIR FNAME NUM _STR

$ ls
b1.text b2.text b3.text b4.text b5.text

$ ./add_prefix.sh 
Input Directory (Blank is Cancel.) : .
Target directory is "."
Input Common Filename(Blank is 0mission): b
Common Filename is "b"
Input Target Extension(Blank is Omission): text
Extension is "text"
Input prefix: a
Prefix is "a"
b1.text b2.text b3.text b4.text b5.text
*** Successful.

$ ls
ab1.text ab2.text ab3.text ab4.text ab5.text