for-group: better check of group name and fixed make argument

A few issues came up while testing the `for-group' script in one of the
projects based on this pipeline that are being fixed with this commit:

  1) We are ultimately using the `sg' command to use the specified group,
     not `chgrp'. So in cases where `chgrp' has problems, this would cause
     a wrong error. So for the test of the given group's existance, we are
     now directly calling `sg'.

  2) In the call to `make' we were mistakenly giving make the `$2' (which
     is `make' on the command-line) argument. Since `./for-group' now takes
     the group name as its first argument, this should have been `$3'.

  3) To help in readability, and also allow for group names with a space,
     `reproducible_paper_group_name' is now defined and exported before the
     final call to `sg'.

1 files changed, 9 insertions, 5 deletions

diff --git a/for-group b/for-group
index 1d96fc3..4ada15f 100755
--- a/for-group
+++ b/for-group
@@ -57,16 +57,19 @@ if [   "x$1" = x          ]; then
     exit 1
 fi
 
+
+
+
+
 # Make sure the given group is usable.
 testfile=".reproducible-pipeline-group-test"
-echo "Just for a test" > $testfile
-if chgrp $1 $testfile; then
+if sg "$1" "echo test > $testfile"; then
     rm $testfile
     if   [ "x$2" = xconfigure ]; then script="./configure"
-    elif [ "x$2" = xmake      ]; then script=".local/bin/make $2"
+    elif [ "x$2" = xmake      ]; then script=".local/bin/make $3"
     else
         echo "$0: a third argument is necessary."
-        echo "It specifies the action: 'configure' or 'make'"
+        echo "It specifies the action: either 'configure' or 'make'"
         exit 1
     fi
 else
@@ -87,4 +90,5 @@ fi
 # We are also exporting a special variable so `./configure' and Make can
 # prepare for sanity checks and avoid re-doing the whole analysis with a
 # typo (not using this script properly after configuration).
-sg $1 "umask u+r,u+w,g+r,g+w,o-r,o-w,o-x && export reproducible_paper_group_name=$1 && $script"
+export reproducible_paper_group_name="$1"
+sg "$1" "umask u+r,u+w,g+r,g+w,o-r,o-w,o-x && $script"