missing quotes and fix cat no such file or directory

commands/exim_forwardadd.sh

@@ -6,4 +6,4 @@ echo "Forward TO email: "
 read emailto
 
 DIR=/etc/exim4/forward
-echo "$(cat $DIR/$emailfrom)$emailto," > "$DIR/$emailfrom"
+echo "$([[ -f $DIR/$emailfrom ]] && cat $DIR/$emailfrom)$emailto," > "$DIR/$emailfrom"

commands/exim_forwarddel.sh

@@ -7,4 +7,4 @@ read emailto
 
 DIR=/etc/exim4/forward
 sed -i "s/$emailto,//g" "$DIR/$emailfrom"
-[[ ! -s $DIR/$emailfrom ]] && rm -f $DIR/$emailfrom
+[[ ! -s "$DIR/$emailfrom" ]] && rm -f "$DIR/$emailfrom"

commands/exim_forwardlist.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 
 DIR=/etc/exim4/forward
-for file in $DIR/*
+for file in "$DIR/*"
 do
     echo "$file: $(cat $DIR/$file)"
 done

commands/exim_userdel.sh

@@ -7,6 +7,6 @@ read domain
 
 DIR=/etc/exim4/domains
 sed -i "/$username/d" "$DIR/$domain"
-[[ ! -s $DIR/$domain ]] && rm -f $DIR/$domain
+[[ ! -s "$DIR/$domain" ]] && rm -f "$DIR/$domain"
 userdb "$username@$domain" del
 makeuserdb