feat(list): adds --count flag for returning a count of matches

README.md

@@ -206,6 +206,12 @@ pda ls --format csv
 # dogs,four legged mammals,no expiry
 
 # Or TSV, or Markdown, or HTML.
+
+# Just the count of entries.
+pda ls --count
+# 2
+pda ls --count --key "d*"
+# 1
 ```
 
 <p align="center"></p><!-- spacer -->

cmd/list.go

@@ -58,6 +58,7 @@ func (e *formatEnum) Type() string { return "format" }
 
 var (
 	listBase64   bool
+	listCount    bool
 	listNoKeys   bool
 	listNoValues bool
 	listNoTTL    bool
@@ -161,6 +162,11 @@ func list(cmd *cobra.Command, args []string) error {
 		}
 	}
 
+	if listCount {
+		fmt.Fprintln(cmd.OutOrStdout(), len(filtered))
+		return nil
+	}
+
 	if (len(matchers) > 0 || len(valueMatchers) > 0) && len(filtered) == 0 {
 		switch {
 		case len(matchers) > 0 && len(valueMatchers) > 0:
@@ -473,6 +479,7 @@ func renderTable(tw table.Writer) {
 
 func init() {
 	listCmd.Flags().BoolVarP(&listBase64, "base64", "b", false, "view binary data as base64")
+	listCmd.Flags().BoolVarP(&listCount, "count", "c", false, "print only the count of matching entries")
 	listCmd.Flags().BoolVar(&listNoKeys, "no-keys", false, "suppress the key column")
 	listCmd.Flags().BoolVar(&listNoValues, "no-values", false, "suppress the value column")
 	listCmd.Flags().BoolVar(&listNoTTL, "no-ttl", false, "suppress the TTL column")

testdata/help-list.ct

@@ -10,6 +10,7 @@ Aliases:
 
 Flags:
   -b, --base64          view binary data as base64
+  -c, --count           print only the count of matching entries
   -o, --format format   output format (table|tsv|csv|markdown|html|ndjson) (default table)
   -f, --full            show full values without truncation
   -h, --help            help for list
@@ -29,6 +30,7 @@ Aliases:
 
 Flags:
   -b, --base64          view binary data as base64
+  -c, --count           print only the count of matching entries
   -o, --format format   output format (table|tsv|csv|markdown|html|ndjson) (default table)
   -f, --full            show full values without truncation
   -h, --help            help for list

testdata/list-count.ct

@@ -0,0 +1,9 @@
+$ pda set a@lc val-a
+$ pda set b@lc val-b
+$ pda set c@lc val-c
+$ pda ls lc --count
+3
+$ pda ls lc --count --key "a*"
+1
+$ pda ls lc --count --key "z*"
+0