report: print header at the beginning of the output

doc/Changelog

@@ -1,4 +1,6 @@
 pgcenter (0.6.2) unstable; urgency=low
+  * report: print header at the beginning of the output
+  * top/report: refactoring aligning
   * adjust header's styles of iostat/nicstat tabs in top utility
   * added support for pg_stat_database.checksum_failures (pg-12)
   * added support of pg_stat_progress_cluster and pg_stat_progress_create_index views

report/report.go

@@ -61,7 +61,7 @@ func RunMain(args []string, opts ReportOptions) {
 func doReport(r *tar.Reader, opts ReportOptions) error {
 	var prevStat, diffStat stat.PGresult
 	var prevTs time.Time
-	var linesPrinted int8
+	var linesPrinted int8 = repeatHeaderAfter // initial value means print header at the beginning of all output
 
 	// read files headers continuously, read stats files requested by user and skip others.
 	for {
@@ -159,7 +159,8 @@ func formatReport(d *stat.PGresult, opts *ReportOptions) {
 
 // printStatHeader periodically prints names of stats columns
 func printStatHeader(printedNum int8, cols []string, opts ReportOptions) int8 {
-	if printedNum >= repeatHeaderAfter {
+
+	if printedNum >= repeatHeaderAfter && opts.Context.Aligned {
 		fmt.Printf("         ")
 		for i, name := range cols {
 			fmt.Printf("\033[%d;%dm%-*s\033[0m", 37, 1, opts.Context.ColsWidth[i]+2, name)