Fix help check

fucopy.sh

 #! /bin/sh
 
-if [ $# -lt 1 ] || [ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]; then
+if [ $# -lt 1 ] || ([ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]); then
     printf "Usage: %s <pattern>\n" $(basename $0) >&2
     printf "Supply a pattern matching files to be copied, e.g. '*.pdf'\n" >&2
     printf "Execute within the directory containing 'grades.csv'\n" >&2

fudist.sh

 #! /bin/sh
 
-if [ $# -lt 1 ] || [ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]; then
+if [ $# -lt 1 ] || ([ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]); then
 	printf 'Usage: %s [FILE]...\n' "$(basename $0)" >&2
 	printf 'Supply file(s) to be distributed into the respective Submission attachment(s)\n' >&2
 	printf "Execute within the directory containing 'grades.csv'\n" >&2

fufixpdf.sh

 #! /bin/sh
 
-if [ $# -ne 0 ] || [ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]; then
+if [ $# -ne 0 ] || ([ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]); then
     printf "Usage: %s\n" $(basename $0) >&2
     printf "Execute within the directory containing 'grades.csv'\n" >&2
     exit 1

fuxournalexport.sh

 #! /bin/sh
 
 xournal=${XOURNAL:-xournalpp}
-if [ $# -ne 1 ] || [ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]; then
+if [ $# -ne 1 ] || ([ ! -f 'grades.csv' ] && [ ! -f 'grades.xls' ]); then
     printf "Usage: %s <list of suffix(es)>\n" $(basename $0) >&2
     printf "Supply a suffix to be appended to the name of the exported file\n" >&2
     printf "E.g., %s '_graded'\n" $(basename $0) >&2

fuzip.sh

 #! /bin/sh
 
 dir=$1
-if [ $# -lt 2 ] || [ ! -f "$dir/grades.csv" ] && [ ! -f "$dir/grades.xls" ]; then
+if [ $# -lt 2 ] || ([ ! -f "$dir/grades.csv" ] && [ ! -f "$dir/grades.xls" ]); then
     printf "Usage: %s <directory> <pattern1> [pattern2] ...\n" $(basename $0) >&2
     printf "Supply a pattern matching files to be added to the zip, e.g. '*.pdf'\n" >&2
-    printf "Execute within the directory containing 'grades.csv'\n" >&2
+    printf "Execute on the directory containing 'grades.csv'\n" >&2
     exit 1
 fi