#!/bin/sh
# 0 pad filenames starting with a number in the current directory
# Copyright 2012 Alan Alberghini <414N@slacky.it>
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR IMPLIED
# WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
# EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

# This script renames a bunch of files in the current directory matching 
# FILE_PATTERN adding prepending 0s to their numbers in order to see them
# sorted in directory listings etc.
# Script arguments:
# $1 - (OPTIONAL) number of digits that the number inside the filename should
#      have. It's used only if its value is greater than the value 
#      automatically computed from the number of files in the directory.

# The regex corresponding to the files to be renamed.
FILE_PATTERN='^[0-9]+'

# Function rename_file
# Renames the given file with the correct 0-padding
# Arguments:
# $1 - filename of the file to rename
function rename_file()
{
	# Extract the number part from the filename using FILE_PATTERN
	NUMBER=`echo "$1" | egrep -o $FILE_PATTERN`

	# Extract the number of significant digits
	NUMBER_TRIMMED=$(seq $NUMBER $NUMBER)

	# Store the remainder of the file name
	FILE_REMAINDER="`echo "$1" | sed -e "s|$NUMBER||"`"

	# If the extracted NUMBER has less significant digits than NUM_DIGITS,
        # the file is renamed.

	if [ ${#NUMBER_TRIMMED} -le $NUM_DIGITS ]
	then
		mv "$1" `printf %0${NUM_DIGITS}d $(( 10#$NUMBER ))`"$FILE_REMAINDER"
	fi
}
# This variable contains the number of 0s wanted by the user, or 0 if not
# specified
NUM_ZERO_USR=${1:-0}

# The modified regex for find. find expects a regex string matching the entire
# path, so, for searching in current directory, './' has to be prepended to
# the pattern string, as '.*' has to be appended to match the rest of the
# filename
FIND_FILE_PATTERN=`echo $FILE_PATTERN | sed -e 's|\^|\^./|'`'.*'

# The find command which will be used hereon.
FIND_BASECOMMAND="find . -type f -maxdepth 1 -regex $FIND_FILE_PATTERN"

# The number of files that need to be renamed. We only look to files matching
# FILE_PATTERN
NUM_FILES=`$FIND_BASECOMMAND | wc -l`

# Compute the number of digits needed to count every file. It is done as:
# Ceiling(Log(10, NUM_FILES))
# where:
# Ceiling is the function which returns the minum integer which is greater than its argument;
# Log(10, NUM_FILES) is the logarithm to base 10 of NUM_FILES
# Given that bc lacks a ceiling function, we discard the decimal part of the
# result and then add 1 to it.
NUM_DIGITS_NEEDED=$((`echo "l($NUM_FILES)/l(10)" | bc -l | cut -d. -f1`+1))

# If the number of digits specified by the user is greater than what has been
# extracted from the number of files, then we'll use the user value hereon.
if [ $NUM_ZERO_USR -gt $NUM_DIGITS_NEEDED ]
then
	NUM_DIGITS=$NUM_ZERO_USR
else
	NUM_DIGITS=$NUM_DIGITS_NEEDED
fi

echo "Going to rename $NUM_FILES files, padding numbers to $NUM_DIGITS inside current directory ."

$FIND_BASECOMMAND -exec basename {} \; | while read FILE; do rename_file "$FILE"; done

#!/bin/bash

# Pads numbers in file names if found.
# See help message for more.

# Set the environment
shopt -s extglob
IFS=""

BCYAN="${BCYAN:-\e[1;36m}"	#Define some color codes, for prettified output.
#BGREEN="${BGREEN:-\e[1;32m}"	#Use environment defaults if they exist.
#BRED="${BRED:-\e[1;31m}"	#set the COLOR variable below to the desired one
#BBLUE="${BBLUE:-\e[1;34m}"
#BMAGENTA="${BMAGENTA:-\e[1;35m}"
RESET="${RESET:-\e[0m}"

COLOR=$BCYAN			#choose which color to use here
#set default padding level
pad=2


# Set up the help dialog
help(){
	local -a help
	help+=( '' 																				)
	help+=( '\tA quick script to zero-pad files that contain numbers.' 									)
	help+=( '\tIt will only pad the first number string it finds in the name, and ignores files without numbers.'	)
	help+=( '' 																				)
	help+=( "\tUsage: \t${COLOR}${0##*/} [-n <num>] <files>${RESET}"										)
	help+=( "\t\t${COLOR}${0##*/} -h${RESET}" 														)
	help+=( '' 																				)
	help+=( '\tUse -n to specify the number of digits to pad, from 1-9.  Defaults to '"$pad"' if not used.'		)
	help+=( '\tIf no files are given, it processes the current directory.' 								)
	help+=( '' 																				)
	help+=( '\t-h prints this help message'															)
	help+=( '' 																				)

	local IFS=$'\n'
	echo -e "${help[*]}"
}


# Process input options
# If "-h" print help & exit.
# If "-n" test for valid inputs and set "pad" variable
# Ignore anything else
while getopts ":hn:" opt; do

     case "$opt" in

          h) help >&2
             exit "2"
          ;;

          n)	if [[ "$OPTARG" =~ [^[:digit:]] ]] || (( "10#$OPTARG" < 1 )) || (( "10#$OPTARG" > 9 )); then
				echo
				echo -e "${COLOR}invalid option: [$OPTARG].${RESET}" >&2
				echo -e "${COLOR}-n must be an integer from 1 to 9${RESET}" >&2
				echo -e "${COLOR}Falling back to the default of $pad${RESET}"
				echo
			else
				pad="$(( 10#$OPTARG ))"
			fi
          ;;

          \?) echo -e "${COLOR}Invalid option: [-$OPTARG].  Ignoring.${RESET}" >&2
          ;;
     esac
done

shift $(( OPTIND - 1 )) ; OPTIND=1

# Now test for files.
# If nothing given, set input parameters to files in current directory.
if [[ -z "$*" ]]; then
	set -- ./*
fi

# Process files in input parameters
re='([^[0-9]*)([0-9]+)(.*)'

for file ; do

	# Ignore files without digits
	[[ "$file" != *[0-9]* ]] && continue

	# Split filename into prefix-digits-suffix
	[[ "$file" =~ $re ]]

	# Pad digits to desired width
	printf -v numpad "%0*d" "$pad" "${BASH_REMATCH[2]##*(0)}"

	# Add old and new filenames to arrays for final processing
	oldfile+=( "$file" )
	newfile+=( "${BASH_REMATCH[1]}${numpad}${BASH_REMATCH[3]}" )

done

# If there are any files to rename, ask to confirm the operation.
# And rename if confirmed.
if [[ -n "${oldfile[*]}" ]]; then

	echo
	echo -e "${COLOR}Rename the following files?${RESET}"
	echo
	for i in "${!oldfile[@]}" ; do
		echo -e "${oldfile[i]/#$PWD/.}\t-->\t${newfile[i]/#$PWD/.}"
	done
	echo

	read -p "(y/n): "

	echo

	case "${REPLY,,}" in

		y*)  	for i in "${!oldfile[@]}" ; do
					mv -n "${oldfile[i]}" "${newfile[i]}"
				done
				echo
				;;

		*)		echo -e "${COLOR}Aborting.${RESET}"
				echo
				exit 1
				;;
	esac

# Otherwise just exit.
else
	echo
	echo -e "${COLOR}No files to rename.${RESET}" >&2
	echo -e "${COLOR}Exiting.${RESET}" >&2
	echo
	exit 1

fi

exit 0