shell之用command在终端判断是否存在这个命令

1、command解释

command命令在shell脚本里面，如果发现有个函数和我们需要执行的命令同名，我们可以用command用来强制执行后面的命令，而不是同名函数，然后我们也可以在shell脚本里面判断莫个命令是否存在，我们平时一般用which命令也行。

2、测试代码

#!/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、运行结果

./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