add list, show commands

The `list` command can be omitted and is the default. The `show` command
retains past output.

```console
$ anissue -h
Usage:
  anissue
  anissue list
  anissue show
```

The implementation uses docopts, the shell variant of docopt [1].
Because of that, wrapping with `--argv0 ''` is necessary when packaging.

[1] http://docopt.org/

5 files changed, 59 insertions, 34 deletions

diff --git a/README.md b/README.md
index b5c8079..30e5135 100644
--- a/README.md
+++ b/README.md
@@ -6,6 +6,14 @@ nix-env -f. -i
 
 ## usage
 
+### list
+
+```console
+anissue list
+```
+
+### show
+
 ```console
-anissue .
+anissue show
 ```
diff --git a/anissue.nix b/anissue.nix
index e0c3496..c2113f0 100644
--- a/anissue.nix
+++ b/anissue.nix
@@ -1,4 +1,5 @@
 { coreutils
+, docopts
 , fetchFromGitHub
 , findutils
 , gawk
@@ -23,8 +24,10 @@ stdenv.mkDerivation {
     for bin in src/*.sh; do
       cp $bin $out/share/$(basename $bin)
       wrapProgram $out/share/$(basename $bin) \
+        --argv0 ''' \
         --set PATH ${lib.makeBinPath [
           coreutils
+          docopts
           findutils
           gawk
           git
@@ -35,6 +38,6 @@ stdenv.mkDerivation {
           tree-grepper
         ]}
     done
-    ln -s $out/share/extract.sh $out/bin/anissue
+    ln -s $out/share/anissue.sh $out/bin/anissue
   '';
 }
diff --git a/shell.nix b/shell.nix
index a85e845..bff07ad 100644
--- a/shell.nix
+++ b/shell.nix
@@ -7,6 +7,7 @@
 pkgs.mkShell {
   buildInputs = [
     pkgs.coreutils
+    pkgs.docopts
     pkgs.findutils
     pkgs.gawk
     pkgs.git
diff --git a/src/anissue.sh b/src/anissue.sh
new file mode 100755
index 0000000..10736c6
--- /dev/null
+++ b/src/anissue.sh
@@ -0,0 +1,45 @@
+#!/usr/bin/env bash
+# Usage:
+#   anissue
+#   anissue list
+#   anissue show
+
+set -efu
+
+eval "$(sed -rn '0,/^$/{ /#!/d; s/^# ?//p }' "$0" | docopts -h- : "$@")"
+
+GREEN='\033[0;32m'
+BOLD=$(tput bold)
+NORMAL=$(tput sgr0)
+NC='\033[0m'
+
+if test $show = true; then
+  "$(dirname "$0")"/extract.sh "$@" | while read -r item; do
+    created_at=$(echo "$item" | jq -r .created_at)
+    file=$(echo "$item" | jq -r .file)
+    heading=$(echo "$item" | jq -r .heading)
+    body=$(echo "$item" | jq -r .body)
+    start_row=$(echo "$item" | jq -r .start_row)
+    end_row=$(echo "$item" | jq -r .end_row)
+
+    echo -e "$GREEN--- $created_at --- $file$NC"
+    echo
+    echo "$BOLD$heading$NORMAL" | fold -s
+    if test -n "$body"; then
+      echo
+      echo "$body" | fold -s
+      echo
+    fi
+    echo
+    cat "$file" | nl -w 4 -s "| " -p -d '' -b a| tail -n +$(($start_row - 2)) | head -n $(($end_row - $start_row + 7))
+    echo
+    echo
+  done
+else
+  "$(dirname "$0")"/extract.sh "$@" | while read -r item; do
+    heading=$(echo "$item" | jq -r .heading)
+    echo "$heading"
+  done
+fi
+
+exit 0
diff --git a/src/extract.sh b/src/extract.sh
index 1e8440d..6422694 100755
--- a/src/extract.sh
+++ b/src/extract.sh
@@ -42,14 +42,6 @@
 #
 # @assigned kirchner@posteo.de
 
-# TODO Add command line modes list and show
-#
-# `anissue list` lists all issues in the current directory
-# `anissue show <issue>` shows an issue using it's id or automatically
-# assigned identifier
-#
-# @assigned aforemny
-
 # TODO Generate and show hash for each issue
 
 
@@ -115,28 +107,4 @@ git ls-files --cached --exclude-standard --other |
         "heading": $heading,
         "start_row": $start_row
       }'
-  done | while read -r item; do
-    created_at=$(echo "$item" | jq -r .created_at)
-    file=$(echo "$item" | jq -r .file)
-    heading=$(echo "$item" | jq -r .heading)
-    body=$(echo "$item" | jq -r .body)
-    start_row=$(echo "$item" | jq -r .start_row)
-    end_row=$(echo "$item" | jq -r .end_row)
-
-    GREEN='\033[0;32m'
-    BOLD=$(tput bold)
-    NORMAL=$(tput sgr0)
-    NC='\033[0m'
-    echo -e "$GREEN--- $created_at --- $file$NC"
-    echo
-    echo "$BOLD$heading$NORMAL" | fold -s
-    if test -n "$body"; then
-      echo
-      echo "$body" | fold -s
-      echo
-    fi
-    echo
-    cat "$file" | nl -w 4 -s "| " -p -d '' -b a| tail -n +$(($start_row - 2)) | head -n $(($end_row - $start_row + 7))
-    echo
-    echo
   done