Linux 10 Shell scripting exercises!

This is the 29th day of my participation in the August More Text Challenge

1. Check the running status of the specified process

#! /bin/bash
NAME=httpd Enter the process name here
NUM=$(ps -ef |grep $NAME |grep -vc grep)
if [ $NUM -eq 1 ]; then
    echo "$NAME running."
else
    echo "$NAME is not running!"
fi
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2. Check whether the user exists

#! /bin/bash
read -p "Please enter user :" user
for i in `awk -F :  '{print $1}' /etc/passwd`
do
        if [ $i= =$user ]
        then
                echo "User already exists!
                exit
        else
                isfind=false
        fi
done
echo "The user does not exist!"
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3. Generate random numbers

#! /bin/bash
read -p "Please enter a randomly generated number of digits :" num
echo $RANDOM | cksum | cut -c 1-$num
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4. Check whether the software package is installed

read -p "Please enter the software package to query :" software

if rpm -q $software &>/dev/null ;

then

    echo "Package installed!"

else

    echo "Package not installed!"

fi
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5. Check whether the host is alive

ip_list="192.168.254.1 192.168.254.10" Define a host list
for ip in $ip_list;do
        NUM=1
        while [ $NUM -le 3 ];do
                if ping -c 1 $ip > /dev/null;then
                        echo "$ipExist in the network!"
                        break
                else
                        echo "$ipDoes not exist in the network!"
                        break
                fi
        done
done
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6. Check the status of the specified host port

The HOST = 127.0.0.1The host being scanned
PORT="22 80 8080" # Specify the ports to scan
for PORT in $PORT; do # for loop
        if echo &>/dev/null > /dev/tcp/$HOST/$PORT; then
                echo    "$PORT open"
        else
                echo    "$PORT close"
        fi
done
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7. Obtain the HOST IP address

#! /bin/bash
IP=$(ip address show | awk '/ ^ [0-9] + : / {}; /inet.*global/ {print gensub(/(.*)\/(.*)/, "\\1", "g", $2)}')
echo "$IP"
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8. Check whether the file or directory exists

#! /bin/bash

if [ $# -eq 0 ];then
    echo "No parameters have been entered, please enter parameters"
    echo "Usage:$0[file name | directory name]"
fi

if [ -f The $1 ]; then
    echo "The file exists"
    ls -l The $1
elif [ -d The $1 ]; then
    echo "This directory exists"
    ls -ld The $1
else
    echo "The file or directory does not exist"
fi
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9. Display system information

#! /bin/bash
#
HOSTNAME=`hostname`
IP=`ip a show ens33 | grep "inet" | grep -v "inet6" | awk '{print $2}' | cut -d'/' -f1`
SYSTEM=`cat /etc/centos-release`
CORE=`uname -r`
CPU=`cat /proc/cpuinfo | grep 'model name' |uniq | cut -d: -f2`
MEMORY=`free -mh | grep -i "mem" | awk '{print$2}'`
DISKNUM=`fdisk -l | grep -i "/dev" | grep -i "disk" | wc -l`
systemname=("HOSTNAME" "IP" "SYSTEM VERSION" "CORE VERSION" "CPU" "MEMORY SIZE")
systeminfo=("$HOSTNAME" "$IP" "$SYSTEM" "$CORE" "$CPU" "$MEMORY")
for s in `seq 1 $DISKNUM`;do
    eval DISK$s=`fdisk -l | grep -i "/dev" | grep -i "disk" | head -$s | tail -1|  awk '{print $2$3$4}' | cut -d', ' -f1`
    eval systeminfo[$(($s+5=))]'$'DISK$s
    systemname[$(($s+5=))]"DISK$s SIZE"
done
for i in The ${! systeminfo[*]};do
    echo "-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --"
    printf "|%-15s| %-43s|\n" "${systemname[$i]}" "${systeminfo[$i]}"
done
echo "-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --"
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10. Check whether the entered IP address is an IP address

#! /bin/bash
IP=The $1
if [[ $IP= ~ ^ [0-9] {1, 3} \. [0-9] {1, 3} \. [0-9] {1, 3} \. [0-9] {1, 3} $]];then
   FIELD1=$(echo $IP|cut -d. -f1)
   FIELD2=$(echo $IP|cut -d. -f2)
   FIELD3=$(echo $IP|cut -d. -f3)
   FIELD4=$(echo $IP|cut -d. -f4)
   if [ $FIELD1 -le 255 -a $FIELD2 -le 255 -a $FIELD3 -le 255 -a $FIELD4 -le 255 ]; 
   then
            echo "$IPIt's an IP address!"
        else
            echo "$IPNot an IP address!"
        fi
    else
        echo "IP address format is wrong!"
fi
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