No bug: Add /m30 string modifier

code/sonalyze/help.txt

@@ -166,6 +166,12 @@ Summary of print modifiers:
 
     duration/sec  -> 12345
 
+  Strings are normally printed in their full length but can be limited to
+  a maximum of 30 characters by /m30:
+
+    JobName       -> supercalifragilisticexpialidocious
+    JobName/m30   -> supercalifragilisticexpialidoc
+
 ## Available field names
 
 By running a command with `-fmt help`, extensive help is provided on all

code/sonalyze/table/data.go

@@ -67,6 +67,11 @@ func FormatString(val string, ctx PrintMods) string {
 	if (ctx&PrintModNoDefaults) != 0 && val == "" {
 		return "*skip*"
 	}
+	if (ctx & PrintModMax30) != 0 {
+		if len(val) > 30 {
+			return val[:30]
+		}
+	}
 	return val
 }
 

code/sonalyze/table/format.go

@@ -24,9 +24,9 @@ type PrintMods = int
 
 const (
 	// These apply per-field according to modifiers
-	// TODO: These are currently unimplemented.
 	PrintModSec = (1 << iota) // timestamps are printed as seconds since epoch
 	PrintModIso               // timestamps are printed as Iso timestamps
+	PrintModMax30
 
 	// These are for the output format and are applied to all fields
 	PrintModFixed      // fixed format
@@ -133,6 +133,8 @@ func addField(
 	if before, after, found := strings.Cut(fieldName, "/"); found {
 		var m PrintMods
 		switch after {
+		case "m30":
+			m = PrintModMax30
 		case "sec":
 			m = PrintModSec
 		case "iso":