contrib: add basic bash completion for lncli

contrib/lncli.bash-completion

@@ -0,0 +1,53 @@
+# bash programmable completion for lncli
+# copy to /etc/bash_completion.d and restart your shell session
+# Copyright (c) by Andreas M. Antonopoulos
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+_lncli() {
+    local cur prev words=() cword
+    local lncli
+
+    # lncli might not be in $PATH
+    lncli="$1"
+
+    COMPREPLY=()
+    _get_comp_words_by_ref -n = cur prev words cword
+
+    case "$prev" in
+        # example of further completion
+        newaddress)
+            COMPREPLY=( $( compgen -W "p2wkh np2wkh p2pkh" -- "$cur" ) )
+            return 0
+            ;;
+    esac
+
+    case "$cur" in
+        -*=*)	# prevent nonsense completions
+            return 0
+            ;;
+        *)
+            local helpopts globalcmds
+
+            # get the global options, starting with --
+            if [[ -z "$cur" || "$cur" =~ ^- ]]; then
+                globalcmds=$($lncli help 2>&1 | awk '$1 ~ /^-/ { sub(/,/, ""); print $1}')
+            fi
+
+            # get the regular commands
+            if [[ -z "$cur" || "$cur" =~ ^[a-z] ]]; then
+                helpopts=$($lncli help 2>/dev/null | awk '$1 ~ /^[a-z]/ { print $1; }' )
+            fi
+
+            COMPREPLY=( $( compgen -W "$helpopts $globalcmds" -X "*," -- "$cur" ) )
+    esac
+} &&
+complete -F _lncli lncli
+
+# Local variables:
+# mode: shell-script
+# sh-basic-offset: 4
+# sh-indent-comment: t
+# indent-tabs-mode: nil
+# End:
+# ex: ts=4 sw=4 et filetype=sh