feat(script): List all snappable datasets (#1)

pacman-zfs-snapshot.sh

@@ -43,6 +43,20 @@ function set_severity () {
     fi
 }
 
+function get_globally_snappable_datasets () {
+    local datasets_list
+    # For all datasets show their 'space.quico:auto-snapshot' property; only
+    # print dataset name in column 1 and property value in column 2. In awk
+    # limit this list to datasets where tab-delimited column 2 has exact
+    # string '^true$' then further limit output by eliminating snapshots
+    # from list, i.e. dataset names that contain an '@' character.
+    datasets_list="$(zfs get -H -o 'name,value' 'space.quico:auto-snapshot' | \
+                     awk -F'\t' '{if($2 ~ /^true$/ && $1 !~ /@/) print $1}')"
+    while IFS= read -r dataset; do
+        globally_snappable_datasets+=("${dataset}")
+    done <<<"${datasets_list}"
+}
+
 function write_pkg_list_oneline () {
     local unabridged_pkg_list_oneline
     if [[ "${severity}" == 'imp' ]]; then
@@ -75,6 +89,9 @@ function main () {
     local severity
     set_severity
 
+    local -a globally_snappable_datasets
+    get_globally_snappable_datasets
+
     local pkg_list_oneline
     write_pkg_list_oneline