cut command, case and select statement

The cut command 
		common parameters: 
		-C Character Character 
		-d delimiter delimiter 
		-f field fields (columns) 
		--output-delimiter output DELIMITER 

		Example: 
		# 12345 echo | cut -c2 
		2 
		# echo 12345 | cut -c1,4 
		14 
		# 12345 echo | Cut-C2-4 
		234 
		# the ifconfig eth0 | grep Mask | Cut -d "" -F12 | Cut -d ":" -f2 

		# head -1 / etc / the passwd | Cut -d ":". 1 -f , --output-3,4- DELIMITER = "#" 

1.case statement 
(2) case syntax 
	Case "Choice" in 
		"var1") 
			statement 
		;; 
		"var2") 
			statement 
		;; 
		"var3") 
			statement 
		;;
		* )
			statement
	esac

(2) the use of 
	copy from a passage in /etc/init.d/httpd 
	Case "$ 1" in 
	  Start) 
	        Start 
	        ;; 
	  STOP) 
	        STOP 
	        ;; 
	  Status) 
	        Status -p $ {} $ httpd the PidFile 
	        RETVAL = $? 
	        ;; 
	  restart ) 
	        STOP 
	        Start 
	        ;; 
	 *) 
	        echo $ "Usage: $ {PROG Start | STOP | restart | condrestart | reload | Status | fullstatus | Use the graceful | Help | configtest}" 
	        Exit 1 
	esac 

	----------- --------- 
	example: sshd script 
	# / bin / bash! 
	Case "$ 1" in 
	Start)  
	# service sshd start
		pid = `pidof sshd` 
		IF [the -Z PID $]; the then 
			/ usr / sbin / the sshd 
			echo" Starting sshd: [OK] " 
		the else 
			echo" service sshd (pid $ pid) already exists. " 
		Fi	 
		;; 

	STOP) 
	# service sshd stop 
		pid = `pidof sshd` 
		IF [the -z $ pid]; the then 
			echo" service sshd has stopped " 
		the else 
			killall sshd &> / dev / null 
			echo" stop sshd: [OK] " 
		fi 
		;; 

	restart) 
	# restart 
		pid = `pidof sshd` 
		IF [the -z $ pid]; the then 
			echo" stop sshd: [failure] " 
			/ usr / sbin / sshd 
			echo" starting sshd: [OK] " 
		the else 
			echo" stop sshd: [OK ] "
			/usr/sbin/sshd
		fi 
		;; 
	
	status) 
	# View state 
		pid = `pidof sshd` 
		IF [the -z $ pid]; the then 
			echo" sshd service has been suspended, " 
		the else 
			echo" service sshd (pid $ pid) is running ... " 
		fi 
		;; 
	
	*) 
	# If the parameters are not start | stop | restart | time status, the prompt 
		echo" usage: /root/ssh1.sh {start | stop | restart | Status} " 
	esac 



	Example: write a shell script, pass into a parameter (the letter), to determine the size of the incoming letters or lowercase 
	#! / bin / bash 

	Case "$ 1" in 
		    [AZ]) 
		    echo "capital" 
		    ;; 
		    [az]) 
		    echo "lowercase" 
		    ;; 
		    *) 
		    echo "not the letter"
		    exit 1
	esac
	-----------------------------------

	#!/bin/bash

	if [[ "$ 1" = ~ [AZ]]]; then - ~ symbol matching means 
		    echo "uppercase" 
	elif [[ "$. 1" = ~ [AZ]]]; the then 
		    echo "lower case" 
	the else 
		    echo "is not the letters " 
	fi 



2. the SELECT 
	the SELECT expression is an extension to apply a bash, the introduction from ksh. 
2.1 Syntax 

	PS3 = "prompt" - to use PS3 to output the message 
	select var in Choice1 Choice2 Choice3 ... 
	do 
		echo "................." 
	DONE 

2.2 with select do a selection menu 
	#! / bin / bash 

	PS3 = "Please select the type of phone you're using" 

	the sELECT HUAWEI Xiaomi phone in the iPhone OPPO samsung lenovo meizu 
	do 
		Case "$ phone" in 
		        the iPhone) 
		        echo "you are using the $ phone"
		        ;; 
		        *) 
		        echo "you are using Phone $" 
		        echo "Android" 
		        BREAK 
		        ;; 
		esac 
	DONE