如果grep找到它正在查找的内容，则执行X else Y [英] If grep finds what it is looking for do X else Y

问题描述

在这个声明中，我试图匹配如果路径/ app / $ var1（应用程序名称）中存在版本（$ var2）

  if 
 find / app / $ var1 -maxdepth 1 -type l -o -type d | grep $ var2＃在一个不错的列表中结果，我可以手动获得一个真正的匹配。 
＃如果找到匹配，则执行命令。 
 $ realcmd$ @
 rc = $？ 
 exit $ rc 
 else 
 echo不匹配，您正在查找的版本不存在
 fi 
  

当前代码：
这包括我所有的代码（未清理）。
命令我运行：./xmodule load firefox / 3.6.12
此版本退出

 ＃！/ bin / bash 
＃一些命令的钩子
 $ b $ #echo $ @＃在xmodule之后输入的sting值
 
 cmd = $ （basename$ 0）
 #echo叫做$ cmd
 
 if [[$ cmd =xmodule]] 
然后
 realcmd ='/ app / modules / 0 / bin / modulecmd tcsh'
 
＃验证参数
 fi 
＃检查$ @是否包含值/以确定是否请求特定版本。 
 case 
 * / *）
 echohas slash
 var1 = $（echo$ @| grep -Eio'\s\ w *'）＃获取应用程序名称并将其放入var1 
 echo $ var1＃不打印应为firefox
 var2 = $（echo$ @| grep -o'[^ /] * $'）＃获取版本名称并将其放入var2 
 echo $ var2 
＃检查/ app / appname / $ b $中是否存在版本号/ find / app / $ var1  - noleaf -maxdepth 1 -type l -o -type d | grep $ var2;然后
 $ realcmd$ @
出口$？ 
 else 
回声不匹配，您正在查找的版本不存在
＃此处是否应该有退出？ 
 fi 
 ;; 
 
 *）
 echo没有斜杠
 ;; 
 esac 
  

输出：
mycomputer [9:55 am] [user / Desktop / script] - > ./xmodule load firefox / 3.6.12
'斜杠

3.6.12
不匹配，您的版本寻找不存在

如果有空白（高于3.6.1），应该有应用程序名称。我现在意识到，这一定是我的问题，它会使用我可能只是/ app的路径。
但是我不认为我改变了那部分代码中的任何东西。

解决方案

您可以使用整个grep管道作为 if 语句的条件。使用 grep -q 来防止打印它找到的匹配（除非你想打印它）。我也简化了退出（如果你只是立即使用它，不需要在变量中存储 $？）。结果如下：

  if find/ app / $ var1-maxdepth 1 -type l -o -type d | grep -q$ var2;然后
 $ realcmd$ @
出口$？ 
 else 
回声不匹配，您正在查找的版本不存在
＃此处是否应该有退出？ 
 fi 
  

顺便说一句，既然你要在$ realcmd后立即退出，你可以使用 exec $ realcmd$ @用$ realcmd替换shell，而不是将$ realcmd作为子进程运行。

In this statement I am trying to match if a version ($var2) exist in the path /app/$var1 (application name)

if 
find /app/$var1 -maxdepth 1 -type l -o -type d | grep $var2 #results in a nice list where i can manually get a true match.
# if match is found then execute command.
$realcmd "$@"
    rc=$?
    exit $rc
else
echo "no match, the version you are looking for does not exist"
fi

current code: this include all my code (not cleaned). command I run: "./xmodule load firefox/3.6.12" this version does exit

#!/bin/bash
# hook for some commands

#echo $@  #value of sting that is entered after "xmodule"

cmd=$(basename "$0")
#echo "called as $cmd"

if [[ $cmd = "xmodule" ]]
then
    realcmd='/app/modules/0/bin/modulecmd tcsh'

    # verify parameters
fi
# check if $@ contains value "/" to determine if a specific version is requested.
case "$@" in
*/*)
    echo "has slash"
var1=$(echo "$@" | grep -Eio '\s\w*') # Gets the aplication name and put it into var1
echo $var1   # is not printed should be "firefox"
var2=$(echo "$@" | grep -o '[^/]*$')  # Gets version name and put it into var2 
echo $var2 
# Checking if version number exist in /app/appname/
if find /app/$var1 -noleaf -maxdepth 1 -type l -o -type d | grep $var2; then
    $realcmd "$@"
    exit $?
else
    echo "no match, the version you are looking for does not exist"
    # Should there be an exit here?
fi
    ;;

*)
    echo "doesn't have a slash"
    ;;
esac

output: mycomputer [9:55am] [user/Desktop/script] -> ./xmodule load firefox/3.6.12 'has slash

3.6.12 no match, the version you are looking for does not exist

Where there is a blank (above 3.6.1) there should be the application name. I am now realizing that this must be my problem sins the path that it uses i likely just /app. But I do not think I changed anything in that part of the code.

解决方案

You can use the entire grep pipeline as the condition of the if statement. Use grep -q to keep it from printing the match it finds (unless you want that printed). I also simplified the exit (there's no need to store $? in a variable if you're just going to use it immediately). Here's the result:

if find "/app/$var1" -maxdepth 1 -type l -o -type d | grep -q "$var2"; then
    $realcmd "$@"
    exit $?
else
    echo "no match, the version you are looking for does not exist"
    # Should there be an exit here?
fi

BTW, since you're going to exit immediately after $realcmd, you could use exec $realcmd "$@" to replace the shell with $realcmd instead of running $realcmd as a subprocess.

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