Shell exercises (14)

Exercise 1:Print a line with only one number

Requirements: title, a text document with only a number of lines to print out

Reference Answer:

#!/bin/bash# date:2018 March 16 f=/etc/groupline= ' wc-l $f |awk ' {print $} ' for L in ' seq 1 $line ' do n= ' Sed-n "$l" p $f |gre P-o ' [0-9] ' |wc-l ' if [$n-eq 1] then sed-n "$l" p $f fidone

Exercise 2: drawing a lottery script

Requirements:

1, write a script execution, enter the name, generate a random number 01-99 between the number.

2, if the same name repeated input, the captured number is the result of the first crawl,

3, the previous number has been captured, the next time can not appear the same number.

4, the first input name, the screen output information, and the name and number recorded in the file, the program can not quit

Continue to wait for other students to enter.

Reference Answer:

#!/bin/bash# date:2018 March 16 while :d o    read -p  "Please input  your name: " name    if [ -f /tmp/draw.log ];then         a= ' cat /tmp/draw.log | awk -f  ': '   ' { print $1} ' | grep  ' $name '     if [  ' $a  !=  ' $name '   ];then        number= ' echo  $RANDOM  |awk -F  ""   ' {print $2 $3} '         while :         do            c= ' Cat  /tmp/draw.log |awk -F  ":"   ' {print $2} ' |grep  "$number" '              if [  "$number"  ==  "$c"  ];then                 echo  "Number exist."                 number= ' Echo   $RANDOM  | awk -F  "  ' {print $2 $3} '              else                 break             fi        done         echo  "$name: $number" |tee -a /tmp/draw.log    else         number= ' cat /tmp/draw.log | grep  "$name"  | awk -F   ":"   ' {print $2} '         echo  $number          echo  "Repeat name."     fielse    number= ' echo  $RANDOM  |awk  ' {print $2  $3} "    echo " $name:  $number "|tee -a /tmp/draw.logfidone

Exercise 3: guessing numbers

Requirements: Write a guess the number of the script, when the user entered the number and the preset number (randomly generated a number less than 100), the direct exit, otherwise let the user input, and prompted the user's number is larger or smaller than the preset number.

Reference Answer:

#!/bin/bash# date:2018 March 16 n= ' echo  $RANDOM  |awk -F  ""   ' {print $2 $3} ' ' while :d o    read -p  ' please guess in [0-99]: " m     expr  $m  + 1 >/dev/null 2>&1    if  [ $? -ne  "0"  ];then        echo -e   "\033[41;37m please input number! \033[0m"          continue    fi    if [  $n  -eq  $m  ];then         echo -e  "\033[34m bingo! \033[0m"          exit    elif [  $n  -lt  $m  ];then        echo  "bigger!"         continue    else        echo  "smaller!"         continue    fidone

Exercise 4: downloading files

Requirement: Create a function that can accept two parameters:

1. The first parameter is a URL, you can download the file, the second parameter is the directory, that is, the location of the download after the save;

2. If the user-given directory does not exist, create the directory

3. If the given directory exists, download the file; Download command after the execution of the test file download success or not; If successful, then > return 0 to the calling script, otherwise, return 2 to the calling script;

Reference Answer:

#!/bin/bash# date:2018 March 16 if [$#-ne 2];then echo "Usage $ URL dirname" Exit 1fi[!-D-$] && mkdir-p    $2CD $2wget $1if [$?-eq 0];then echo "Download ok!"    Exit 0else echo "FAIL!!!" Exit 2fi

Exercise 5: Listing subdirectories

Requirements: The script can take parameters or without, parameters can have more than one, each parameter must be a directory, the script checks the number of parameters, if equal to 0, the current directory itself is listed, otherwise, display each parameter contains subdirectories

Reference Answer:

#!/bin/bash# date:2018 March 16 if [$# = = 0];then ls-ld ' pwd ' else for I in ' seq 1 $# ' do a= $i Echo ' LS ${!a} "ls-l ${!a} |grep ' ^d ' Donefi

Exercise 6: Obtaining a network card IP

Requirements: Prompt the user to enter the name of the network card, then we use the script to output the IP card. Seemingly simple, but need to consider a number of aspects, such as we entered the name of the network card does not match the specification, how to deal with. The name conforms to the specification, but there is no way to deal with this NIC

Reference Answer:

#!/bin/bash# date:2018 March 16 while :d o    read -p  "Please input  a network name:  " e    e1= ' echo " $e " | sed " S/[0-9]//g '     e2= ' echo  "$e"  | sed  ' s/[a-za-z]//g '      if [ -z  $e  ];then        echo  "You  input nothing "        continue    elif  [ -z  $e 1 ];then        echo  "You input  number? but network name start with ens+number.  "         continue    elif [ -z  $e 2 ];then         echo  "You input letter ? but network  named ens+number  "        continue    else         break    fidoneip () {    ifconfig|  grep -wa1  "$:" |tail -1|awk  ' {print $2} '}myip= ' ip  $e ' if [ -z $ myip ];then    echo  "sorry, the network  $e  is not  exist. " else    echo  "your network ip is:  $myip" fi

Shell exercises (14)