如果grep的发现它是什么期待脱颖而出做X别的ÿ [英] IF grep finds what it is looking fore do X else Y

问题描述

在此声明我想如果匹配一个版本（$ VAR2）在路径/应用/ $ VAR1（应用程序名）存在

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

目前的code：
这包括所有我的code（不清洗）。
命令我跑：./xmodule负荷的Firefox / 3.6.12
这个版本确实退出

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

输出：
MYCOMPUTER [上午9:55] [用户/桌面/脚本] - > ./xmodule加载的firefox / 3.6.12
有斜线

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

3.6.12
不匹配，您正在寻找的版本不存在

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

哪里有空白（3.6.1以上）应该有应用程序名称。我现在意识到这一定是我的问题的罪，它使用我可能只是/应用程序的路径。
但我不认为我在code的那部分改变任何东西。

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.

推荐答案

您可以使用整个grep的管道仿佛语句的的状态。使用的grep -q 来保持它打印找到匹配（除非你想要的打印）。我还简化了出口（有没有必要 $？来存储在一个变量，如果你只是要立即使用它）。这里的结果是：

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

顺便说一句，因为你要$ realcmd后立即退出，你可以使用 EXEC $ realcmd$ @来替换$外壳realcmd而不是运行$ realcmd作为子进程。

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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