Added perms plugin (#1752)

* Added perms plugin

* HTTPS -> HTTP for comment URL

* Added a README

* Updated TOF comment

* Pulled in updates by apjanke with minor tweaks

plugins/perms/README.md

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+## Perms
+
+Plugin to handle some unix filesystem permissions quickly
+
+### Usage
+
+* `set755` recursively sets all directories located within the current working directory and sub directories to octal 755.
+* `set644` recursively sets all files located within the current working directory and sub directories to octal 644.
+* `fixperms` is a wrapper around `set755` and `set644` applied to a specified directory or the current directory otherwise. It also prompts prior to execution unlike the other two  aliases.

plugins/perms/perms.plugin.zsh

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+# Some useful commands for setting permissions.
+#
+# Rory Hardy [GneatGeek]
+# Andrew Janke [apjanke]
+
+### Aliases
+
+# Set all files' permissions to 644 recursively in a directory
+alias set644='find . -type f -print0 | xargs -0 chmod 644'
+
+# Set all directories' permissions to 755 recursively in a directory
+alias set755='find . -type d -print0 | xargs -0 chmod 755'
+
+### Functions
+
+# fixperms - fix permissions on files and directories, with confirmation
+# Returns 0 on success, nonzero if any errors occurred
+fixperms () {
+  local opts confirm target exit_status chmod_opts use_slow_mode
+  zparseopts -E -D -a opts -help -slow v+=chmod_opts
+  if [[ $# > 1 || -n "${opts[(r)--help]}" ]]; then
+    cat <<EOF
+Usage: fixperms [-v] [--help] [--slow] [target]
+
+  target  is the file or directory to change permissions on. If omitted,
+          the current directory is taken to be the target.
+
+  -v      enables verbose output (may be supplied multiple times)
+
+  --slow  will use a slower but more robust mode, which is effective if
+          directories themselves have permissions that forbid you from
+          traversing them.
+
+EOF
+    exit_status=$(( $# > 1 ))
+    return $exit_status
+  fi
+
+  if [[ $# == 0 ]]; then
+    target="."
+  else
+    target="$1"
+  fi
+  if [[ -n ${opts[(r)--slow]} ]]; then use_slow=true; else use_slow=false; fi
+
+  # Because this requires confirmation, bail in noninteractive shells
+  if [[ ! -o interactive ]]; then
+    echo "fixperms: cannot run in noninteractive shell"
+    return 1
+  fi
+
+  echo "Fixing perms on $target?"
+  printf '%s' "Proceed? (y|n) "
+  read confirm
+  if [[ "$confirm" != y ]]; then
+    # User aborted
+    return 1
+  fi
+
+  # This xargs form is faster than -exec chmod <N> {} \; but will encounter
+  # issues if the directories themselves have permissions such that you can't
+  # recurse in to them. If that happens, just rerun this a few times.
+  exit_status=0;
+  if [[ $use_slow == true ]]; then
+    # Process directories first so non-traversable ones are fixed as we go
+    find "$target" -type d -exec chmod $chmod_opts 755 {} \;
+    if [[ $? != 0 ]]; then exit_status=$?; fi
+    find "$target" -type f -exec chmod $chmod_opts 644 {} \;
+    if [[ $? != 0 ]]; then exit_status=$?; fi
+  else
+    find "$target" -type d -print0 | xargs -0 chmod $chmod_opts 755
+    if [[ $? != 0 ]]; then exit_status=$?; fi
+    find "$target" -type f -print0 | xargs -0 chmod $chmod_opts 644
+    if [[ $? != 0 ]]; then exit_status=$?; fi
+  fi
+  echo "Complete"
+  return $exit_status
+}