Linux case command (compare values) [Basic Guide]

The case command in Linux is an intelligent way to compare the value of something with various standards.

If an occurrence is positive, it allows commands to be executed.

Each case is an expression that corresponds to a pattern.

The “)” operator ends a list of patterns and starts a list of commands.

What separates one pattern from another is “;;”.

At the end of the case, you must finish with the esac instruction (case on the contrary).

Example of a script that, depending on the user’s UID, prints a different message:

#! /bin/bash 
ID=$ (id -u) 
case “$ID” in 
0) 
echo “You are the root.” ; 
echo “Congratulations!” 
;; 
1000) 
echo “You are Uira.” 

;;
100 [1-9])
echo “You are another user”
esac
echo “end”;

If the value of the ID variable is 0, it will print a congratulations message. If it is equal to 1000, print “you are Uira”. If it’s between 1001 and 1009, print “You’re another user.

If executed with the user uira, who has a UID equal to 1000:

$. /meucase 
You are Uira. 

End

If run as root:

$ I sweat. /mycase 
You are root. 
Congratulations! 

End

The case is better than using the “if” command several times to compare something with various patterns.

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