add top-history

plugins/available/history-search.plugin.bash

@@ -1,3 +1,4 @@
+# shellcheck shell=bash
 cite about-plugin
 about-plugin 'search history using the prefix already entered'
 

plugins/available/history-substring-search.plugin.bash

@@ -1,3 +1,4 @@
+# shellcheck shell=bash
 cite about-plugin
 about-plugin 'search history using the substring already entered'
 

plugins/available/history.plugin.bash

@@ -1,3 +1,4 @@
+# shellcheck shell=bash
 cite about-plugin
 about-plugin 'improve history handling with sane defaults'
 
@@ -9,3 +10,30 @@ export HISTCONTROL=${HISTCONTROL:-ignorespace:erasedups}
 
 # resize history to 100x the default (500)
 export HISTSIZE=${HISTSIZE:-50000}
+
+top-history() {
+	about 'print the name and count of the most commonly run tools'
+
+	if [[ -n $HISTTIMEFORMAT ]]; then
+		# To parse history we need a predictable format, which HISTTIMEFORMAT
+		# gets in the way of. So we unset it and set a trap to guarantee the
+		# user's environment returns to normal even if the pipeline below fails.
+		# shellcheck disable=SC2064
+		trap "export HISTTIMEFORMAT='$HISTTIMEFORMAT'" RETURN
+		unset HISTTIMEFORMAT
+	fi
+
+	history \
+		| awk '{
+				a[$2]++
+			}END{
+				for(i in a)
+				printf("%s\t%s\n", a[i], i)
+			}' \
+		| sort --reverse --numeric-sort \
+		| head \
+		| column \
+			--table \
+			--table-columns 'Command Count,Command Name' \
+			--output-separator ' | '
+}