feat: implements --tags

Implements `--tags`, which lists all tags in use.

cmd/cheat/cmd_tags.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/cheat/cheat/internal/config"
+	"github.com/cheat/cheat/internal/sheets"
+)
+
+// cmdTags lists all tags in use.
+func cmdTags(opts map[string]interface{}, conf config.Config) {
+
+	// load the cheatsheets
+	cheatsheets, err := sheets.Load(conf.Cheatpaths)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, fmt.Sprintf("failed to list cheatsheets: %v", err))
+		os.Exit(1)
+	}
+
+	// write sheet tags to stdout
+	for _, tag := range sheets.Tags(cheatsheets) {
+		fmt.Println(tag)
+	}
+}

cmd/cheat/docopt.txt

@@ -11,6 +11,7 @@ Options:
   -r --regex            Treat search <phrase> as a regex
   -s --search=<phrase>  Search cheatsheets for <phrase>
   -t --tag=<tag>        Return only sheets matching <tag>
+  -T --tags             List all tags in use
   -v --version          Print the version number
 
 Examples:
@@ -33,6 +34,9 @@ Examples:
   To list all available cheatsheets:
     cheat -l
 
+  To list all tags in use:
+    cheat -T
+
   To list available cheatsheets that are tagged as "personal":
     cheat -l -t personal
 

cmd/cheat/main.go

@@ -76,6 +76,9 @@ func main() {
 	case opts["--list"].(bool):
 		cmd = cmdList
 
+	case opts["--tags"].(bool):
+		cmd = cmdTags
+
 	case opts["--search"] != nil:
 		cmd = cmdSearch
 

cmd/cheat/str_usage.go

@@ -20,6 +20,7 @@ Options:
   -r --regex            Treat search <phrase> as a regex
   -s --search=<phrase>  Search cheatsheets for <phrase>
   -t --tag=<tag>        Return only sheets matching <tag>
+  -T --tags             List all tags in use
   -v --version          Print the version number
 
 Examples: