shell腳本處理從一個命令是錯誤的，從迴音

Question

被excuted你好，我是新來shell script，我需要處理error從命令來進行excuted內echo像下面

echo -e "some internal command that I can't share \nq" | nc localhost 10000 

我想說的

if [[ there's no error ]] 

Answer 1

嘗試

echo "YOUR SUPERSECRET COMMAND" | nc localhost 10000 | grep "Your expected error" 
if [[ $? -eq 0 ]]; then 
    echo "Do something useful with error" 
else 
    echo "Success" 
fi 

grep上匹配返回0，並返回1，當它沒有找到匹配的字符串。

Answer 2

shell變量$?會給你退出代碼。所以，你可以這樣做：

echo -e "some internal command that I can't share \nq" | nc localhost 10000 
rc=$? 

if [[ $rc == 0 ]]; then 
    echo "success" 
fi 

或者乾脆，

if echo -e "some internal command that I can't share \nq" | nc localhost 10000; then 
    echo "success" 
fi 

Answer 3

這裏是做這件事的簡潔的方式：

internalcommand &>/dev/null 2>&1 && echo OK || echo FAILED

如果internalcommand成功確定將被打印到標準輸出，如果失敗，失敗的原因是打印。

在Bash v4上測試的筆記