gzip.sh

#!/bin/sh
#
# This script is only necessary if you have a *very* old gzip.
#
GZIP_DL="https://ftp.gnu.org/gnu/gzip"
GZIP_XZ="gzip-1.12.tar.xz"
GZIP_DIR="$(basename $GZIP_XZ .tar.xz)"
GZIP_URL="$GZIP_DL/$GZIP_XZ"
ORIGIN_DIR="$(CDPATH= cd -- "$(dirname -- "$0")" && pwd)"

# Dont continue on error.
set -e

# Help text.
if [ "$1" = '-h' ]; then
    echo >&2 "Usage: $0 [clean]"
    echo >&2
    echo >&2 'Specify "clean" to remove gzip, otherwise it will be downloaded and built.'
    exit 1
fi

# Optional cleanup if requested.
if [ "$1" = 'clean' ]; then
    rm -fv "$ORIGIN_DIR/gzip" "$ORIGIN_DIR/gunzip" "$ORIGIN_DIR/zcat"
    rm -rfv "$GZIP_DIR"
    rm -fv "$ORIGIN_DIR/$GZIP_XZ"
    exit
fi

# Download gzip.
if [ ! -f "$GZIP_XZ" ]; then
    wget "$GZIP_URL"
fi

# Extract gzip.
if [ ! -d "$GZIP_DIR" ]; then
    xzcat "$GZIP_XZ" | tar xf -
fi

# Compile gzip.
if [ ! -x "$GZIP_DIR/gzip" ]; then
   cd "$GZIP_DIR" && ./configure && gmake -j$(nproc)
   cd "$ORIGIN_DIR"
fi

# Copy compiled binaries to working directory.
copy() {
   test ! -x "$2" && cp -v "$1" "$2"
}

copy "$GZIP_DIR/gzip" "$ORIGIN_DIR/gzip"
copy "$GZIP_DIR/gunzip" "$ORIGIN_DIR/gunzip"
copy "$GZIP_DIR/zcat" "$ORIGIN_DIR/zcat"