yubikey-plugin Enhancement

* Update the README.md file
  * Add key listing logic (auto-truncating if too long)
  * Some output cosmetics

plugins/yubikey/README.md

@@ -9,3 +9,14 @@ This plugin will first try to detect location of the 'opensc-pkcs11.so' library,
 Afterwards, it will try to detect if a 'shared ssh-agent' is already running, through a file in /run (preferred, but must be pre-created with the proper permissions), or in /tmp (fallback).
 
 Then it will define several aliases.
+
+## Optional Parameters
+
+These parameters can be set before source-ing oh-my-zsh to customize the settings:
+
+`YUBI_SHOWKEYS`
+> If set to '1' or 'y' or 'yes', will list the keys contained in the 'shared ssh-agent'
+
+`YUBI_SSHAGENT_AUTOINIT`
+> If set to '1' or 'y' or 'yes', will automatically initialize the 'shared ssh-agent' if one is not found
+

plugins/yubikey/yubikey.plugin.zsh

@@ -4,6 +4,7 @@ local _libname='opensc-pkcs11.so'
 local _sshfiledir="/run/user/$UID"
 local _sshfile='ssh_agent'
 local _sshpath=''
+local _ellipsis='......'
 
 if [[ -z $OPENSC ]]; then
     for f in $(locate "/${_libname}"); do
@@ -26,20 +27,33 @@ alias yubi-insert="ssh-add -s $OPENSC"
 alias yubi-eject="ssh-add -e $OPENSC"
 
 if [[ -r $_sshpath ]]; then
-    echo "Common SSH Agent detected."
+    echo -n "Common SSH Agent detected. "
     source $_sshpath
 else
-    echo -n "Common SSH Agent not detected."
+    echo -n "Common SSH Agent not detected. "
     case "${(U)YUBI_SSHAGENT_AUTOINIT}" in
         1|Y|YES)
-            echo -n " Auto-initializing... "
+            echo -n "Auto-initializing... "
             yubi-init
             echo "done."
             ;;
         *)
-            echo " Autoinit not enabled. Use 'yubi-init' to manually init."
+            echo "Autoinit not enabled. Use 'yubi-init' to manually init."
             ;;
     esac
 fi
 
+case "${(U)YUBI_SHOWKEYS}" in
+    1|Y|YES)
+        ssh-add -L | while read ln; do
+            if (( ${#ln} >= COLUMNS )); then
+                newlen=$(( COLUMNS - ${#_ellipsis} - 1 ))
+                halflen=$(( newlen / 2 ))
+                ln="${ln:0:$halflen}${_ellipsis}${ln: -$halflen}"
+            fi
+            echo "$ln"
+        done
+        ;;
+esac
+
 # vim: set ft=zsh ts=4 sts=4 et ai :