Add replace-spdx-license.sh script

This script is to replace an SPDX license ID by another one.
I.e, it's to perform an actual re-licensing of a given file.

A way to use the script is this:

    replace-spdx-license.sh  --from LGPL-3.0-or-later \
			      --to  "Apache-2.0 WITH LLVM-exception" \
			      some-file-to-relicense.cc

	* relicensing-scripts/replace-spdx-license.sh: New script.

Signed-off-by: Benjamin De Kosnik <bkoz@gnu.org>
Signed-off-by: Ben Woodard <woodard@redhat.com>
Signed-off-by: Chenxiong Qi <cqi@redhat.com>
Signed-off-by: Dodji Seketeli <dodji@redhat.com>
Signed-off-by: Giuliano Procida <gprocida@google.com>
Signed-off-by: Jan Engelhardt <jengelh@inai.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Mark Wielaard <mark@klomp.org>
Signed-off-by: Matthias Klose <doko@ubuntu.com>
Signed-off-by: Matthias Maennich <maennich@google.com>
Signed-off-by: Ondrej Oprala <ondrej.oprala@gmail.com>
Signed-off-by: Roland McGrath <roland@hack.frob.com>
Signed-off-by: Sinny Kumari <ksinny@gmail.com>
Signed-off-by: Slava Barinov <v.barinov@samsung.com>

relicensing-scripts/replace-spdx-license.sh

@@ -0,0 +1,75 @@
+#!/bin/sh
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+# Author: Dodji Seketeli <dodji@redhat.com>
+
+from_license_id=
+to_license_id=
+input_file=
+prog=$0
+
+display_usage()
+{
+    echo "$prog: [options] --from <from-spdx-license-id> --to <to-spdx-license-id> <file>"
+    echo "  where options can be:"
+    echo "   -h|--h		display this help"
+}
+
+main()
+{
+    header=$(head --lines=5 $input_file | grep "SPDX-License-Identifier:")
+    if test "x$header" != x; then
+	license=$(echo "$header" | sed -r "s/^.*(SPDX-License-Identifier:)[ 	]*([^*/]+).*$/\2/")
+    fi
+
+    if test "x$license" != x -a "$license" = "$from_license_id"; then
+	sed -i -r "s/$from_license_id/$to_license_id/" $input_file
+	exit 0
+    fi
+
+    exit 1
+}
+
+# This program takes at least 5 arguments
+if test $# -lt 5; then
+    >&2 display_usage
+    exit 1
+fi
+
+# Parse parameters
+while test $# -gt 1; do
+    case "$1" in
+	-h|--h)
+	    display_usage
+	    exit 0
+	    ;;
+
+	-f|--from)
+	    from_license_id=$2
+	    shift
+	    ;;
+
+	-t|--to)
+	    to_license_id=$2
+	    shift
+	    ;;
+
+	-*)
+	    >&2 display_usage
+	    exit 1
+	    ;;
+
+	*)
+	    input_file="$1"
+	    ;;
+    esac
+    shift
+done
+
+if test $# -lt 1; then
+    >&2 display_usage
+    exit 1
+fi
+
+input_file=$1
+
+main