如何从Mac上的Shell脚本获取输出？

Question

I am looking to run a command in shell script and check its output.If it has certain text, I want to set a global variable to particular string.Below is what I have done so far. The command ~/Library/Android/sdk/tools/android list | grep 'The "android" command is deprecated. ~/Library/Android/sdk/tools/android list | grep 'The "android" command is deprecated. works in terminal however it doesn't seem to work in shell script. What am I missing here?

#!/bin/bash
Android_Command=''    

MKCOMMAND='~/Library/Android/sdk/tools/android list | grep 'The "android" command is deprecated.''
RESP=$($MKCOMMAND)
echo $RESP

if [ '$RESP'=='The "android" command is deprecated.' ]; then
 Android_Command='Version2'
else
 Android_Command='Version1'
fi

Following is the output that I get

 ~/Library/Android/sdk/tools/android: No such file or directory

Answer 1

From your last edit, it has become clear that you were not executing the script from your terminal but rather you were just executing a single line from it.

In shell scripts, anything inside a single quote is not subject to shell expansion. Having said that, both ~ and | cannot be quoted.

Redirections are created by the shell before execution. This means MKCOMMAND cannot be executed because the pipe | will be treated as a parameter to the command android .

So how do we deal with this kind of script? Don't quote any redirections.

#!/bin/bash

if ~/Library/Android/sdk/tools/android list | grep -q 'The "android" command is deprecated.'; then
 Android_Command='Version2'
else
 Android_Command='Version1'
fi

The if statement accepts a complex statement. grep -q will return zero if it finds the string and non-zero otherwise.

Answer 2

Try running your command directly instead (without using the MKCOMMAND variable):

RESP=$(~/Library/Android/sdk/tools/android list | grep 'The "android" command is deprecated.')
echo $RESP
...

This (quick!) hack might bypass some Bash quoting issues you may be having.