check-deb.sh

#!/usr/bin/env sh
# Author: Jongmin Kim <jmkim@debian.org>
# Usage: ./check-deb.sh file.deb

# Strict mode
set -eu

# $1 as $DEB
DEB="${1:-}"

# Check if $DEB is supplied
if [ -z "$DEB" ]; then
  echo "Usage: $0 file.deb" >&2
  exit 1
fi

# Check if $DEB is a regular file
if [ ! -f "$DEB" ]; then
  echo "Error: $DEB is not a regular file (not found or dir)" >&2
  exit 2
fi

# Extract members from $DEB ar archive (.deb)
if ! MEMBERS="$(ar t "$DEB" 2>/dev/null)"; then
  echo 'Error: Not a Debian binary package (not an ar archive)' >&2
  exit 3
fi

# Locate the tar members
CONTROL_TAR="$(printf '%s\n' "$MEMBERS" | awk '/^control\.tar/ { print; exit; }')"
DATA_TAR="$(printf '%s\n' "$MEMBERS" | awk '/^data\.tar/ { print; exit; }')"

# Check the required members:
#         debian-binary (not checked by this script)
#         control.tar
#         data.tar
#     See https://manpages.debian.org/unstable/dpkg-dev/deb.5.en.html
if [ -z "$CONTROL_TAR" ] || [ -z "$DATA_TAR" ]; then
  echo 'Error: Not a Debian binary package' >&2
  exit 4
fi

# Create a temp work dir
TMPDIR="$(mktemp -d "${TMPDIR:-/tmp}/check-deb.XXXXXX")"
trap 'rm -rf "$TMPDIR"' EXIT

# Extract the control tar
ar --output "$TMPDIR" x "$DEB" "$CONTROL_TAR"
tar -C "$TMPDIR" -xf "$TMPDIR/$CONTROL_TAR"

# Check if control file exists
CONTROL="$TMPDIR/control"
if [ ! -f "$CONTROL" ]; then
  echo 'Error: Not a Debian binary package (control file missing)' >&2
  exit 5
fi

# Extract the pkg version and pkg name from the control file
VER="$(awk -F': ' '/^Version: / { print $2; }' "$CONTROL")"
PKG="$(awk -F': ' '/^Package: / { print $2; }' "$CONTROL")"

# Print the pkg version
echo "Version: $VER"

# Extract the data tar
ar --output "$TMPDIR" x "$DEB" "$DATA_TAR"
tar -C "$TMPDIR" -xf "$TMPDIR/$DATA_TAR"

# Check for the copyright file
COPYRIGHT="/usr/share/doc/$PKG/copyright"
if [ -f "$TMPDIR$COPYRIGHT" ]; then
    echo "Has copyright file in $COPYRIGHT"
else
    echo "Missing copyright file in $COPYRIGHT"
fi