Migration

+700 net lines, good luck to the reviewer.

CMS/scripts/das-cmssw

+#!/usr/bin/env bash
+
+if [[ $# -lt 2 ]]; then
+    echo "$0 image command [args]" >&2
+    exit 2
+fi
+
+img=$1
+shift # rm first element of $@
+
+case "$img" in
+    *cc7)
+        export CMSSW_VERSION=CMSSW_10_6_30
+        ;;
+    *el8)
+        export CMSSW_VERSION=CMSSW_12_4_0
+        ;;
+    *)
+        tput setaf 1
+        echo "Unknown Linux version. Abort."
+        tput op
+        exit 1
+        ;;
+esac
+
+$img <<'SCRIPT' -s $CMSSW_VERSION "$@"
+CMSSW_VERSION=$1
+shift
+function source_CMS_setup() { source $DAS_BASE/CMS/setup > /dev/null ; }
+source_CMS_setup
+if [ ! -d $DAS_BASE/$CMSSW_VERSION ]; then
+    echo "$CMSSW_VERSION could not be found. Are you sure that it has been installed?"
+    exit 1
+fi
+cd $DAS_BASE/$CMSSW_VERSION
+eval $(scram runtime -sh) # cmsenv
+cd - > /dev/null
+"$@"
+SCRIPT