crushPng.sh

#!/usr/bin/env bash

# Resize all png images in a given directory, using pngquant.

# Usage:
# bash crushPng.sh "path/to/files/"

# Check that a path has been provided from the cli.
if [ -z "$1" ]; then
    echo "A path must be provided."
    exit 1
fi

# Check that pngquant is installed.
if [ -z $(type "pngquant") ]; then
    echo "pngquant command not found. Install before running this script."
    exit 1;
fi

# Replace trailing slash
path=$(echo $1 | sed -e 's/\/$//')

for file in $(find "$path" | grep .png | sed 's/^[0-9]*://g'); do
    pngquant 256 $file --ext -new.png
    newFile=$(echo $file | sed 's/.png/-new.png/g')

    # If a new file was created by pngquant then rename that new file name
    # to the original file name, otherwise notify that the file did not
    # need to be resized.
    if [ -f "$newFile" ]; then
        mv $newFile $file
        echo "$file resized."
    else
        echo "$file did not need to be resized."
    fi
done

# This command can take a while when running over a directory with
# lots of bug PNGs in it. Notify the user when this process is complete.
say "Crush PNG command complete."

ppiLocator.sh

#!/usr/bin/env bash

# Lists the ppi for all images. If a second argument is supplied then
# only images with that ppi will be shown.

# Usage:
# bash ppiLocator.sh "path/to/files/" "*.png" 72 eq

# Check that a path has been provided from the cli.
if [ -z "$1" ]; then
    echo "No path provided."
    exit 1
fi

# Check that a file type has been provided from the cli.
if [ -z "$2" ]; then
    echo "No file type provided."
    exit 1
fi

path=$(echo $1 | sed -e 's/\/$//')
files=$(find $path -type f -name $2)

for file in $files; do
    ppi=$(identify -verbose -units PixelsPerInch -format '%x' $file 2>/dev/null)
    ppi=$(printf "%.0f" $ppi)

    # If no ppi is passed from the cli then list the ppi for each file.
    if [ -z "$3" ]; then
        echo "$file is $ppi ppi"
    else
        # if operator not specified
        if [ -z "$4" ]; then

            if [ "$ppi" -eq "$3" ]; then
                echo "$file is $ppi ppi"
            fi
        else
            # if operator specified
            if [ "$4" = "lt" -a "$ppi" -lt "$3" ]; then
                echo "$file is $ppi ppi"
            fi

            if [ "$4" = "gt" -a "$ppi" -gt "$3" ]; then
                echo "$file is $ppi ppi"
            fi

            if [ "$4" = "eq" -a "$ppi" -eq "$3" ]; then
                echo "$file is $ppi ppi"
            fi
        fi
    fi
done

rename.sh

#!/usr/bin/env bash

# Renames files in a folder from 1 to the total number of files. For
# example if there are 100 files with different names, this script
# will renames them from 1 to 100 with the given extension, say png.

# Usage: bash rename.sh "path/to/file/sequence" "png" 1

# Check if the first argument from the command line is present.
if [ -z "$1" ]; then
        echo "No directory provided."
        exit 1
fi

# Check if the second argument from the command line is present.
if [ -z "$2" ]; then
    echo "No file extension provided."
        exit 1
fi

# Replace trailing slash
path=$(echo $1 | sed -e 's/\/$//')

# If the directory doesn't exist then exit with a warning.
if [ ! -d $path ]; then
        echo "No such directory exists."
        exit 1
fi

# Sort files in alphanumerical order.
files=$(ls $path | sort -k1,1n)

i=0

# If there is a third parameter then assign i to it's value.
if [ ! -z "$3" ]; then
        i=$3
fi

# Increment the counter and rename the file.
for file in $files; do
        ((i++))
        mv "$path/$file" "$path/$i.$2"
done