Bash 脚本：如何查找以一个字符开头的行？

Question

I'm trying to find some lines in a text file that begin with only one (+).

my file:

--- step31.php  2017-03-10 18:34:59.430949110 +0330
+++ step32.php  2017-03-10 18:34:59.430949110 +0330
@@ -1,6 +1,6 @@
 <?php
 defined('_JEXEC') or die;
-JLoader::register('BannersHelper', JPATH_COMPONENT . '/helpers/banners.php');
+JLoader::register('BannersHelper', JPATH_ADMINISTRATOR . '/components/com_banners/helpers/banners.php');
 class BannersViewBanner extends JViewLegacy{
     protected $form;
     protected $item;
@@ -32,7 +32,7 @@
             JToolbarHelper::save2copy('banner.save2copy');}
         if (empty($this->item->id)) {
             JToolbarHelper::cancel('banner.cancel');} else {
-            if ($this->state->params->get('save_history', 0) && $user->authorise('core.edit')) {
+            if ($this->state->params->get('save_history', 0) && $canDo->get('core.edit')) {
                 JToolbarHelper::versions('com_banners.banner', $this->item->id);}

desired output:

+JLoader::register('BannersHelper', JPATH_ADMINISTRATOR . '/components/com_banners/helpers/banners.php');
+            if ($this->state->params->get('save_history', 0) && $canDo->get('core.edit')) {

I use grep '^+' but output is:

+++ step32.php  2017-03-10 18:34:59.430949110 +0330
+JLoader::register('BannersHelper', JPATH_ADMINISTRATOR . '/components/com_banners/helpers/banners.php');
+            if ($this->state->params->get('save_history', 0) && $canDo->get('core.edit')) {

Answer 1

You can use:

grep '^+[^+]' file

+JLoader::register('BannersHelper', JPATH_ADMINISTRATOR . '/components/com_banners/helpers/banners.php');
+            if ($this->state->params->get('save_history', 0) && $canDo->get('core.edit')) {

Regex ^+[^+] will match + at start followed by anything except + thus giving you expected output.