What are the two representations of shell judgment?

This article is to share with you what the two expressions of shell judgment are, the editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article. Don't say much, follow the editor to have a look.

Test test expression that returns either ture or false

There is another way to use square brackets []

If ["$name1" = "Jack"] and if test "$name1" = "Jack" are equivalent

Be sure to pay attention to the spaces when using it.

If ["$name1" = "Jack"] and if ["$name1" = "Jack"] are different.

/ / =

Let's take a look at two logical operators, AND and OR

AND, logic and (& &), abbreviated to-a when we use it

OR, logic or (| |), abbreviated to-o

Add one more condition. When the user name is "Jack" or "Kelly", only one of the conditions can be met.

If ["$name1" = "Jack"-o "$name1" = "Kelly"]

Or

If test "$name1" = "Jack"-o "$name1" = "Kelly"

Next, use the use of AND-a, which requires that the conditions are met at the same time.

Echo "Please enter the login user name:"

Read name1

Echo "Please enter your password:"

Read password1

If ["$name1" = "Jack"-a "$password1" = "1234"]

Then

Echo "login success"

Else

Echo "login failed, please check your user name or password"

Fi

These are the two expressions of shell judgment, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.