Add command to create a symbolic link

documentation/kitfile.markdown

@@ -112,3 +112,7 @@ Available commands are:
     immediately. Useful for showing manual actions needed (eg. allowing an
     application to use Accessibility features) without them being buried
     among the entire output of a run.
+
+* symlink _SOURCE_ _DESTINATION_
+
+    Creates a symbolic link at _DESTINATION_ that points to _SOURCE_.

kitout.sh

@@ -133,6 +133,7 @@ function process_kitfile {
             clone)      clone_repository $argument ;;
             brewfile)   brewfile "$argument" ;;
             install)    install_file $argument ;;
+            symlink)    symlink $argument ;;
             remind)     remind "$argument" ;;
 
             cron_entry) add_to_crontab "$argument" ;;
@@ -255,6 +256,19 @@ function install_file {
     fi
 }
 
+function symlink {
+    local source="$1"
+    local target="$2"
+
+    action "symbolic linking '$target' to '$source'"
+    if [ -e "$target" -a ! -L "$target" ]; then
+        error "cannot create symlink: '$target' already exists"
+    else
+        rm -f "$target"
+        ln -s "$source" "$target"
+    fi
+}
+
 function add_to_crontab {
     local line="$*"
     local tab="$(mktemp '/tmp/kitout.crontab.XXXXX')"

tests/symlink.bats

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+
+bold=$'\e'[1m
+yellow=$'\e'[33m
+magenta=$'\e'[35m
+reset=$'\e'[0m
+
+@test symlink {
+    [ ! -f /tmp/symlink.kitfile ]
+    [ ! -f /tmp/exists ]
+
+    run ./kitout.sh tests/symlink.kitfile
+    echo "$output"
+
+    [ $status -eq 1 ]
+
+    [ -f /tmp/symlink.kitfile ]
+    [ -L /tmp/symlink-to-symlink.kitfile ]
+    [ "${lines[2]}" == "${yellow}=== symbolic linking '/tmp/symlink-to-symlink.kitfile' to '/tmp/symlink.kitfile'${reset}" ]
+
+    [ -e /tmp/exists -a ! -L /tmp/exists ]
+    [ "${lines[3]}" == "${yellow}=== symbolic linking '/tmp/exists' to '/tmp/symlink.kitfile'${reset}" ]
+    [ "${lines[4]}" == "${bold}${magenta}*** cannot create symlink: '/tmp/exists' already exists${reset}" ]
+}
+
+function setup_file {
+    teardown
+}
+
+function teardown {
+    rm -f /tmp/symlink.kitfile /tmp/exists
+}

tests/symlink.kitfile

@@ -0,0 +1,9 @@
+# make sure file exists
+install tests/symlink.kitfile   /tmp/symlink.kitfile
+install tests/symlink.kitfile   /tmp/exists
+
+# link to it
+symlink /tmp/symlink.kitfile    /tmp/symlink-to-symlink.kitfile
+
+# should not work, cannot replace files
+symlink /tmp/symlink.kitfile    /tmp/exists