Initial commit of usage function

Wrote more helpful helptext for this. Now we print each command, what it
does, and each command's additional options.

Also added a help command.

1 files changed, 33 insertions, 7 deletions

diff --git a/andbackup.sh b/andbackup.sh
index 5ada59d..b16f970 100755
--- a/andbackup.sh
+++ b/andbackup.sh
@@ -21,6 +21,35 @@ set -u
 backups=/sdcard/andbackup
 
 
+usage() {
+  # NOTE: The maximum width of this text should be 68 chars. This
+  #       will ensure it displays properly on most devices without
+  #       strange wrapping.
+  #       If using vim to reflow, execute ':set tw=65'
+  out="
+Andbackup is a basic Android application (or package) backup and
+restore script. It can backup a single application, or a a list
+of applications provided in a text file (one application name per
+line). It can do the same for application restore.
+
+The default backup path is '/sdcard/andbackup/'.
+
+Usage:
+  andbackup.sh <command> [opts]
+
+Commands:
+  help                    Print this help text
+  backup      <app_name>  Back up a single package
+  restore     <app_name>  Restore a single package
+  list                    List installed packages
+  listbackup  <list_file> Backup packages using a list text file
+  listrestore <list_file> Restore packages from a list text file
+
+"
+  printf "${out}"
+}
+
+
 log() {
   logtype=${1:-}
   logmsg=${2:-}
@@ -215,14 +244,11 @@ main() {
     list_restore_apps ${@}
   elif [ "${cmd}" = 'ls' ] || [ "${cmd}" = 'list' ]; then
     list_apps
+  elif [ "${cmd}" = 'help' ]; then
+    usage
   else
-    printf "Please specify a command\n"
-    printf "Available commands are...\n"
-    printf "  backup\n"
-    printf "  listbackup\n"
-    printf "  restore\n"
-    printf "  listrestore\n"
-    printf "  list\n"
+    lerror "Unknown command '${cmd}'"
+    usage
     return 1
   fi
 }