Add adding entries to crontab

documentation/kitfile.markdown

@@ -100,3 +100,8 @@ Available commands are:
 
     Copies a file found at _SOURCE_ to _DESTINATION_. If _MODE_ is specified,
     the file has that mode applied (any valid arguments to `chmod`).
+
+* cron_entry _MN_ _HR_ _DOM_ _MON_ _DOW_ _CMD_
+
+    Add an entry to the crontab, creating one if necessary. The arguments are
+    described in more detail in the manual: run `man 5 crontab`.

kitout.sh

@@ -118,7 +118,7 @@ function process_kitfile {
         )
         read command argument <<<"$line"
         case "$command" in
-            \#|'')  : ;;
+            \#*|'')     : ;;
             echo)       output "$argument" ;;
             debug)      debug_output "$argument" ;;
             section)    section "$argument" ;;
@@ -128,6 +128,8 @@ function process_kitfile {
             brewfile)   brewfile "$argument" ;;
             install)    install_file $argument ;;
 
+            cron_entry) add_to_crontab "$argument" ;;
+
             *)      error "Unknown command: '$command'" ;;
         esac
     done
@@ -246,4 +248,36 @@ function install_file {
     fi
 }
 
+function add_to_crontab {
+    local line="$*"
+    local tab="$(mktemp '/tmp/kitout.crontab.XXXXX')"
+    local email search
+
+    if ! crontab -l > "$tab" 2>/dev/null; then
+        email=$( git config user.email )
+        [ -z "$email" ] && email='crontab@example.com'
+
+        cat << EOF | sed -e 's/^ *//' > "$tab"
+            MAILTO=$email
+            PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin
+
+            #mn   hr    dom   mon   dow   cmd
+EOF
+        action 'initialising crontab'
+    fi
+
+    search=$(
+        echo "$line" \
+            | sed -e 's/\*/\\*/g' -e 's/  */ */g'
+    )
+    debug "search='$search'"
+
+    if ! grep -q "$search" "$tab"; then
+        echo "$line" >> "$tab"
+        action "added '$line' to crontab"
+    fi
+
+    crontab "$tab"
+}
+
 main "$@"

tests/cron.bats

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+yellow=$'\e'[33m
+reset=$'\e'[0m
+TEMP_CRON=$( mktemp '/tmp/crontab.original.XXXXX' )
+
+@test cron_entry {
+    skip "Triggers a security prompt, run manually"
+
+    if crontab -l > $TEMP_CRON; then
+        crontab /dev/null
+    fi
+
+    run ./kitout.sh tests/cron.kitfile
+    echo "$output"
+
+    [ $status -eq 0 ]
+    [ "${lines[0]}" == "${yellow}=== added '*     *     *     *     *     sleep 1' to crontab${reset}" ]
+
+    if [ "$(stat -f'%z' $TEMP_CRON)" -gt 0 ]; then
+        crontab $TEMP_CRON
+    else
+        crontab /dev/null
+    fi
+}

tests/cron.kitfile

@@ -0,0 +1,2 @@
+            #mn   hr    dom   mon   dow   cmd
+cron_entry  *     *     *     *     *     sleep 1