shell之用command在終端判斷是否存在這個指令

1、command解釋

command指令在shell腳本裡面，如果發現有個函數和我們需要執行的指令同名，我們可以用command用來強制執行後面的指令，而不是同名函數，然後我們也可以在shell腳本裡面判斷莫個指令是否存在，我們平時一般用which指令也行。

2、測試代碼

#!/bin/bash
 
function pwd()
{
    echo "I am pwd function"
}
 
echo "shell run pwd"
pwd
 
echo "shell command pwd"
command pwd
 
if  command -v pwd > /dev/null; then
    echo "pwd command has found"
else
    echo "pwd command has not found"
fi
 
if  command -v pwd1 > /dev/null; then
    echo "pwd1 command has found"
else
    echo "pwd1 command has not found"
fi
       

3、運作結果

./command  

shell run pwd

I am pwd function

shell command pwd

/home/chenyu/Desktop/linux/dabian/python

pwd command has found

pwd1 command has not found