diff --git a/rc/tools/lint.kak b/rc/tools/lint.kak
index a0accd08..63fca562 100644
--- a/rc/tools/lint.kak
+++ b/rc/tools/lint.kak
@@ -1,113 +1,339 @@
-declare-option -docstring %{
-    shell command to which the path of a copy of the current buffer will be passed
-    The output returned by this command is expected to comply with the following format:
-        {filename}:{line}:{column}: {kind}: {message}
-} str lintcmd
+declare-option \
+    -docstring %{
+        The shell command used by lint-buffer and lint-selections.
+
+        It will be given the path to a file containing the text to be
+        linted, and must produce output in the format:
+
+            {filename}:{line}:{column}: {kind}: {message}
+
+        If the 'kind' field contains 'error', the message is treated
+        as an error, otherwise it is assumed to be a warning.
+    } \
+    str lintcmd
 
 declare-option -hidden line-specs lint_flags
-declare-option -hidden range-specs lint_errors
+declare-option -hidden line-specs lint_messages
 declare-option -hidden int lint_error_count
 declare-option -hidden int lint_warning_count
 
-define-command lint -docstring 'Parse the current buffer with a linter' %{
-    evaluate-commands %sh{
-        if [ -z "${kak_opt_lintcmd}" ]; then
-            echo 'fail The `lintcmd` option is not set'
-            exit 1
-        fi
+define-command \
+    -hidden \
+    -params 1 \
+    -docstring %{
+        lint-cleaned-selections <linter>: Check each selection with <linter>.
 
+        Assumes selections all have anchor before cursor, and that
+        %val{selections} and %val{selections_desc} are in the same order.
+    } \
+    lint-cleaned-selections \
+%{
+    # Clear the current contents of the various options.
+    set-option buffer lint_flags %val{timestamp}
+    set-option buffer lint_messages %val{timestamp}
+    set-option buffer lint_error_count 0
+    set-option buffer lint_warning_count 0
+
+    # Create a temporary directory to keep all our state.
+    evaluate-commands %sh{
+        # This is going to come in handy later.
+        kakquote() {
+            printf "'"
+            printf "%s" "$*" | sed "s/'/''/g"
+            printf "'"
+        }
+
+        # Before we clobber our arguments,
+        # let's record the lintcmd we were given.
+        lintcmd="$1"
+
+        # Some linters care about the name or extension
+        # of the file being linted, so we'll store the text we want to lint
+        # in a file with the same name as the original buffer.
         filename="${kak_buffile##*/}"
 
+        # A directory to keep all our temporary data.
         dir=$(mktemp -d "${TMPDIR:-/tmp}"/kak-lint.XXXXXXXX)
-        mkfifo "$dir"/fifo
-        printf '%s\n' "evaluate-commands -no-hooks write -sync $dir/${filename}"
 
+        # A fifo to send the results back to a Kakoune buffer.
+        # FIXME: Should we put the lint output in toolsclient?
+        mkfifo "$dir"/fifo
         printf '%s\n' "evaluate-commands -draft %{
-                  edit! -fifo $dir/fifo -debug *lint-output*
+                  edit! -fifo $(kakquote "$dir/fifo") -debug *lint-output*
                   set-option buffer filetype make
                   set-option buffer make_current_error_line 0
-                  hook -always -once buffer BufCloseFifo .* %{ nop %sh{ rm -r '$dir' } }
               }"
 
+        # Write all the selection descriptions to files.
+        eval set -- "$kak_quoted_selections_desc"
+        i=0
+        for desc; do
+            mkdir -p "$dir"/sel-"$i"
+            printf "%s" "$desc" > "$dir"/sel-$i/desc
+            i=$(( i + 1 ))
+        done
+
+        # Write all the selection contents to files.
+        eval set -- "$kak_quoted_selections"
+        i=0
+        for text; do
+            # The selection text needs to be stored in a subdirectory,
+            # so we can be sure the filename won't clash with one of ours.
+            mkdir -p "$dir"/sel-"$i"/text/
+            printf "%s" "$text" > "$dir"/sel-$i/text/"$filename"
+            i=$(( i + 1 ))
+        done
+
+        # We do redirection trickiness to record stderr from
+        # this background task and route it back to Kakoune,
+        # but shellcheck isn't a fan.
+        # shellcheck disable=SC2094
         ({ # do the parsing in the background and when ready send to the session
 
-        eval "$kak_opt_lintcmd '$dir'/${filename}" | sort -t: -k2,2 -n > "$dir"/stderr
+        for selpath in "$dir"/sel-*; do
+            # Read in the line and column offset of this selection.
+            IFS=".," read -r start_line start_byte _ < "$selpath"/desc
+
+            # Run the linter, and record the exit-code.
+            eval "$lintcmd '$selpath/text/$filename'" |
+                    sort -t: -k2,2 -n |
+                    awk \
+                        -v line_offset=$(( start_line - 1 )) \
+                        -v first_line_byte_offset=$(( start_byte - 1 )) \
+                    '
+                        BEGIN { OFS=":"; FS=":" }
+
+                        /:[1-9][0-9]*:[1-9][0-9]*:/ {
+                            $1 = ENVIRON["kak_bufname"]
+                            if ( $2 == 1 ) {
+                                $3 += first_line_byte_offset
+                            }
+                            $2 += line_offset
+                            print $0
+                        }
+                    ' >>"$dir"/result
+        done
+
+        # Load all the linter messages into Kakoune options.
+        # Yes, shellcheck, we do want line-continuation backslashes
+        # inside the string.
+        # shellcheck disable=SC1004
+        awk -v file="$kak_buffile" -v client="$kak_client" '
+            function kakquote(text) {
+                # \x27 is apostrophe, escaped for shell-quoting reasons.
+                gsub(/\x27/, "\x27\x27", text)
+                return "\x27" text "\x27"
+            }
 
-        # Flags for the gutter:
-        #   stamp l3|{red}█ l11|{yellow}█
-        # Contextual error messages:
-        #   stamp 'l1.c1,l1.c1|kind:message' 'l2.c2,l2.c2|kind:message'
-        awk -F: -v file="$kak_buffile" -v stamp="$kak_timestamp" -v client="$kak_client" '
             BEGIN {
+                OFS=":"
+                FS=":"
                 error_count = 0
                 warning_count = 0
             }
-            /:[1-9][0-9]*:[1-9][0-9]*: ([Ff]atal )?[Ee]rror/ {
-                flags = flags " " $2 "|{red}█"
-                error_count++
-            }
+
             /:[1-9][0-9]*:[1-9][0-9]*:/ {
-                if ($4 !~ /[Ee]rror/) {
-                    flags = flags " " $2 "|{yellow}█"
+                # Remember that an error or a warning occurs on this line..
+                if ($4 ~ /[Ee]rror/) {
+                    # We definitely have an error on this line.
+                    flags_by_line[$2] = "{Error}!"
+                    error_count++
+                } else if (flags_by_line[$2] ~ /Error/) {
+                    # We have a warning on this line,
+                    # but we already have an error, so do nothing.
+                    warning_count++
+                } else {
+                    # We have a warning on this line,
+                    # and no previous error.
+                    flags_by_line[$2] = "{Information}?"
                     warning_count++
                 }
-            }
-            /:[1-9][0-9]*:[1-9][0-9]*:/ {
-                kind = substr($4, 2)
-                error = $2 "." $3 "," $2 "." $3 "|" kind
-                msg = ""
-                # fix case where $5 is not the last field because of extra colons in the message
+
+                # The message starts with the severity indicator.
+                msg = substr($4, 2)
+
+                # fix case where $5 is not the last field
+                # because of extra colons in the message
                 for (i=5; i<=NF; i++) msg = msg ":" $i
+
+                # Mention the column where this problem occurs,
+                # so that information is not lost.
+                msg = msg "(col " $3 ")"
+
+                # FIXME: I *think* this line is left over from a time
+                # when Kakoune used pipes to delimit items in a list
+                # option. If so, it is entirely useless now... but I
+                # am not 100% sure.
                 gsub(/\|/, "\\|", msg)
-                gsub("'\''", "'"''"'", msg)
-                error = error msg " (col " $3 ")"
-                errors = errors " '\''" error "'\''"
+
+                if ($2 in messages_by_line) {
+                    # We already have a message on this line,
+                    # so append our new message.
+                    messages_by_line[$2] = messages_by_line[$2] "\n" msg
+                } else {
+                    # A brand-new message on this line.
+                    messages_by_line[$2] = msg
+                }
             }
+
             END {
-                print "set-option \"buffer=" file "\" lint_flags " stamp flags
-                gsub("~", "\\~", errors)
-                print "set-option \"buffer=" file "\" lint_errors " stamp errors
-                print "set-option \"buffer=" file "\" lint_error_count " error_count
-                print "set-option \"buffer=" file "\" lint_warning_count " warning_count
-                print "evaluate-commands -client " client " lint-show-counters"
-            }
-        ' "$dir"/stderr | kak -p "$kak_session"
+                for (line in flags_by_line) {
+                    flag = flags_by_line[line]
 
-        cut -d: -f2- "$dir"/stderr | awk -v bufname="${kak_bufname}" '
-            /^[1-9][0-9]*:[1-9][0-9]*:/ {
-                print bufname ":" $0
-            }
-            ' > "$dir"/fifo
+                    print "set-option -add " \
+                        kakquote("buffer=" file) " " \
+                        "lint_flags " \
+                        kakquote(line "|" flag)
+                }
 
-        } & ) >/dev/null 2>&1 </dev/null
+                for (line in messages_by_line) {
+                    msg = messages_by_line[line]
+
+                    print "set-option -add " \
+                        kakquote("buffer=" file) " " \
+                        "lint_messages " \
+                        kakquote(line "|" msg)
+                }
+
+                print "set-option " \
+                    kakquote("buffer=" file) " " \
+                    "lint_error_count " \
+                    error_count
+                print "set-option " \
+                    kakquote("buffer=" file) " " \
+                    "lint_warning_count " \
+                    warning_count
+            }
+        ' "$dir"/result | kak -p "$kak_session"
+
+        # Send any linting errors to the debug buffer,
+        # for visibility.
+        if [ -s "$dir"/stderr ]; then
+            # Errors were detected!"
+            printf "echo -debug Linter errors: <<<\n"
+            while read -r LINE; do
+                printf "echo -debug %s\n" "$(kakquote "  $LINE")"
+            done < "$dir"/stderr
+            printf "echo -debug >>>\n"
+            # FIXME: When #3254 is fixed, this can become a "fail"
+            printf "eval -client %s echo -markup {Error}%s\n" \
+                "$kak_client" \
+                "lint failed, see *debug* for details"
+        else
+            # No errors detected, show the results.
+            printf "eval -client %s lint-show-counters" \
+                "$kak_client"
+        fi | kak -p "$kak_session"
+
+        # We are done here. Send the results to Kakoune,
+        # and clean up.
+        cat "$dir"/result > "$dir"/fifo
+        rm -rf "$dir"
+
+        } & ) >"$dir"/stderr 2>&1 </dev/null
     }
 }
 
+define-command \
+    -params 0..2 \
+    -docstring %{
+        lint-selections [<switches>]: Check each selection with a linter.
+
+        Switches:
+            -command <cmd>      Use the given linter.
+                                If not given, the lintcmd option is used.
+    } \
+    lint-selections \
+%{
+    evaluate-commands -draft %{
+        # Make sure all the selections are "forward" (anchor before cursor)
+        execute-keys <a-:>
+
+        # Make sure the selections are in document order.
+        evaluate-commands %sh{
+            printf "select "
+            printf "%s\n" "$kak_selections_desc" |
+                tr ' ' '\n' |
+                sort -n -t. |
+                tr '\n' ' '
+        }
+
+        evaluate-commands %sh{
+            # This is going to come in handy later.
+            kakquote() {
+                printf "'"
+                printf "%s" "$*" | sed "s/'/''/g"
+                printf "'"
+            }
+
+            if [ "$1" = "-command" ]; then
+                if [ -z "$2" ]; then
+                    echo 'fail -- -command option requires a value'
+                    exit 1
+                fi
+                lintcmd="$2"
+            elif [ -n "$1" ]; then
+                echo "fail -- Unrecognised parameter $(kakquote "$1")"
+                exit 1
+            elif [ -z "${kak_opt_lintcmd}" ]; then
+                echo 'fail The lintcmd option is not set'
+                exit 1
+            else
+                lintcmd="$kak_opt_lintcmd"
+            fi
+
+            printf '%s\n' "lint-cleaned-selections $(kakquote "$lintcmd")"
+        }
+    }
+}
+
+define-command \
+    -docstring %{
+        lint-buffer: Check the current buffer with a linter.
+
+        Set the lintcmd option to control which linter is used.
+    } \
+    lint-buffer \
+%{
+    evaluate-commands -draft %{
+        execute-keys '%'
+        lint-cleaned-selections %opt{lintcmd}
+    }
+}
+
+alias global lint lint-buffer
+
 define-command -hidden lint-show %{
-    update-option buffer lint_errors
+    update-option buffer lint_messages
     evaluate-commands %sh{
-        eval "set -- ${kak_quoted_opt_lint_errors}"
-        shift
+        # This is going to come in handy later.
+        kakquote() {
+            printf "'"
+            printf "%s" "$*" | sed "s/'/''/g"
+            printf "'"
+        }
 
-        s=""
-        for i in "$@"; do
-            s="${s}
-${i}"
+        eval set -- "${kak_quoted_opt_lint_messages}"
+        shift # skip the timestamp
+
+        while [ $# -gt 0 ]; do
+            lineno=${1%%|*}
+            msg=${1#*|}
+
+            if [ "$lineno" -eq "$kak_cursor_line" ]; then
+                printf "info -anchor %d.%d %s\n" \
+                    "$kak_cursor_line" \
+                    "$kak_cursor_column" \
+                    "$(kakquote "$msg")"
+                break
+            fi
+            shift
         done
-
-        printf %s\\n "${s}" | awk -v line="${kak_cursor_line}" \
-                                  -v column="${kak_cursor_column}" \
-            "/^${kak_cursor_line}\./"' {
-                gsub(/"|%/, "&&")
-                msg = substr($0, index($0, "|"))
-                sub(/^[^ \t]+[ \t]+/, "", msg)
-                printf "info -anchor %d.%d \"%s\"\n", line, column, msg
-            }'
     }
 }
 
 define-command -hidden lint-show-counters %{
-    echo -markup linting results:{red} %opt{lint_error_count} error(s){yellow} %opt{lint_warning_count} warning(s)
+    echo -markup "linting results: {Error} %opt{lint_error_count} error(s) {Information} %opt{lint_warning_count} warning(s) "
 }
 
 define-command lint-enable -docstring "Activate automatic diagnostics of the code" %{
@@ -121,54 +347,82 @@ define-command lint-disable -docstring "Disable automatic diagnostics of the cod
     remove-hooks window lint-diagnostics
 }
 
-define-command lint-next-error -docstring "Jump to the next line that contains an error" %{
-    update-option buffer lint_errors
+# FIXME: Is there some way we can re-use make-next-error
+# instead of re-implementing it?
+define-command \
+    -docstring "Jump to the next line that contains a lint message" \
+    lint-next-message \
+%{
+    update-option buffer lint_messages
 
     evaluate-commands %sh{
-        eval "set -- ${kak_quoted_opt_lint_errors}"
+        eval "set -- ${kak_quoted_opt_lint_messages}"
         shift
 
-        for i in "$@"; do
-            candidate="${i%%|*}"
-            if [ "${candidate%%.*}" -gt "${kak_cursor_line}" ]; then
-                range="${candidate}"
+        if [ "$#" -eq 0 ]; then
+            printf 'fail no lint messages'
+            exit
+        fi
+
+        for lint_message; do
+            lineno="${lint_message%%|*}"
+            msg="${lint_message##*|}"
+
+            if [ "$lineno" -gt "$kak_cursor_line" ]; then
+                printf "execute-keys %dg\n" "$lineno"
+                printf "info -anchor %d.%d %s\n" \
+                    "$lineno" "1" "$(kakquote "$msg")"
                 break
             fi
         done
 
-        range="${range-${1%%|*}}"
-        if [ -n "${range}" ]; then
-            printf 'select %s\n' "${range}"
-        else
-            echo 'fail no lint diagnostics'
-        fi
+        # FIXME: should we wrap around like make-next-error?
     }
 }
 
-define-command lint-previous-error -docstring "Jump to the previous line that contains an error" %{
-    update-option buffer lint_errors
+# lint-next-message was previously known as lint-next-error,
+# but it includes warnings too, not just errors.
+alias global lint-next-error lint-next-message
+
+# FIXME: Is there some way we can re-use make-previous-error
+# instead of re-implementing it?
+define-command \
+    -docstring "Jump to the previous line that contains a lint message" \
+    lint-previous-message \
+%{
+    update-option buffer lint_messages
 
     evaluate-commands %sh{
-        eval "set -- ${kak_quoted_opt_lint_errors}"
+        eval "set -- ${kak_quoted_opt_lint_messages}"
         shift
 
-        for i in "$@"; do
-            candidate="${i%%|*}"
+        if [ "$#" -eq 0 ]; then
+            printf 'fail no lint messages'
+            exit
+        fi
 
-            if [ "${candidate%%.*}" -ge "${kak_cursor_line}" ]; then
-                range="${last_candidate}"
+        last_lineno="$kak_cursor_line"
+        last_msg="no previous message"
+
+        for lint_message; do
+            lineno="${lint_message%%|*}"
+            msg="${lint_message##*|}"
+
+            if [ "$lineno" -ge "${kak_cursor_line}" ]; then
+                printf "execute-keys %dg\n" "$last_lineno"
+                printf "info -anchor %d.%d %s\n" \
+                    "$lineno" "1" "$(kakquote "$last_msg")"
                 break
             fi
 
-            last_candidate="${candidate}"
+            last_lineno="$last_lineno"
+            last_msg="$msg"
         done
 
-        if [ $# -ge 1 ]; then
-            shift $(($# - 1))
-            range="${range:-${1%%|*}}"
-            printf 'select %s\n' "${range}"
-        else
-            echo 'fail no lint diagnostics'
-        fi
+        # FIXME: should we wrap around like make-previous-error?
     }
 }
+
+# lint-previous-message was previously known as lint-previous-error,
+# but it includes warnings too, not just errors.
+alias global lint-previous-error lint-previous-message