36. A number of numbers

Demand:

• Use shell to implement it, print only a number of numbers in a text document

Core points:

• Use SED to replace all non -digital characters as empty, and the rest is the number

[[email protected] ~]# cat 36.sh
#!/bin/bash
while read line
do
    n=`echo $line |sed 's/[^0-9]'//g|wc -L`
    if [ $n -eq 1 ]
    then
        echo $line
    fi
done < test.txt
[[email protected] ~]# sh 36.sh
1jieljinve

37. Log cutting archive

Demand:

• system logrotate tools can complete log cutting and archiving. Write a shell script to achieve a similar archived palace 鞥 you
• Join the server output log is 1. Log, requires a daily archive of one, 1. Log becomes 1.log.1 the second day, and the third day becomes 1.log.2, on the fourth day 1. Log.3 , Until 1. Log.5

Core points:

• MV rename
• After changing the name, re -load the service to generate a new log

[[email protected] ~]# cat 37.sh
#!/bin/bash
cd /data/logs
log =1.log
mv_log()
{
    [ -f $1 ] && mv $1 $2
}
[ -f 1.log5 ] && rm -f 1.log.5
for i in  `seq 4 -1 1 `
do
    j=$[$i+1]
    mv_log $log.$i $log.$j
done
mv 1.log 1.log.1
[[email protected] ~]# 

38. Find online IP

Demand:

• Write a shell script and list the online IP of 192.168.0.0/24

Core points:

• for cycle all the IP
• See if IP can ping through

################Q[email protected]~]# Cat 38.SH 
 #!/bin/basn 
 for I in` SEQ 1 254` 
 DO 
     m = `ping -c 4" 192.168.0. $ i "| GREP 'Packets' | AWK -F ',' '{Print $ 3}' | AWK '{Print $ 1}' | AWK -F '%' { Print $ 1} '` 
     if ["$ M" == 0] 
     then 
        echo "192.168.0. $ i online" 
     FI 
 Done 
 ################## 实 ################# 
 ++ SEQ 1 254 
 + for I in '`SEQ 1 254`' 
 ++ AWK '{Print $ 1}' 
 ++ AWK -F % '{PRINT $ 1}' 
 ++ AWK -F, '{Print $ 3}' 
 ++ GREP PACKETS 
 ++ ping -c 4 192.168.0.1 
 + M = 100 
 + '[' 100 == 0 ']' 
 + for I in '`SEQ 1 254`' 
 ++ AWK '{Print $ 1}' 
 ++ AWK -F % '{PRINT $ 1}' 
 ++ AWK -F, '{Print $ 3}' 
 ++ GREP PACKETS 
 ++ PING -C 4 192.168.0.2 
 + M = 100 
 + '[' 100 == 0 ']' 
 + for I in '`SEQ 1 254`' 
 ++ AWK '{Print $ 1}' 
 ++ AWK -F % '{PRINT $ 1}' 
 ++ AWK -F, '{Print $ 3}' 
 ++ GREP PACKETS 
 ++ ping -c 4 192.168.0.3 
 .... 
 ########################## ########[email protected]~]# cat 38_1.SH 
 #!/bin/bash 
 for I in` SEQ 1 254` 
 DO 
     if Ping -C 2 -W 2 192.168.0. $ 1>/dev/null 2>/dev/null ### -W timeout 
     then 
         echo "192.168.0. $ i is common" 
     else 
         echo "192.168.0. $ i not access" 
 Done

39. Check the script syntax error

Demand:

• Write a script to check whether the specified shell script has grammatical errors. If there is an error, first display the error message, and then prompt the user to enter the Q or Q to exit the script.

Core points:

• sh -n

###################Q[email protected]~]# Cat 39.SH 
 #!/bin/bash 
 sh -n $ 1 2> /tmp/sh.err 
 n = `cat sh.err | GREP 'error'` 
 if [-z $ n] 
 then 
     Echo "script correct" 
 else 
     cat /tmp/sh.err 
     Whether the read -p "is launched (q | q):" i 
       if [$ i "==" q "] || [" $ i "==" q "] 
       then 
          exit 
       else 
          vim $ 1 
       FI 
 FI 
 #################### ###################[email protected]~]# sh -x 39.SH 38.SH 
 + sh -n 38.sh 
 ++ GREP ERROR 
 ++ cat /tmp/sh.err 
 + n = '38 .sh: Line 12: Syntax error nearxpected token `done '\' ' 
 + '[' -z 38.SH: Line 12: Syntax error near unexpected token '`done' \ '' ']' 
 39.SH: Line 4: [: Too Many Arguments 
 + cat /tmp/sh.err 
 38.SH: Line 12: Syntax error near unexpected token `done ' 
 38.SH: Line 12: `Done ' 
 + whether to release the script (q | q): 'i 
 Whether to launch a script (q | Q): 
 + '[' '' == q ']' 
 + '[' '' == q ']' 
 + vim 38.SH[email protected]~]# SH 39.SH 37.SH 
 "Correct script" 
 ##################### Reference ################## 
 #!/bin/bash 
 sh -n $ 1 2> /tmp/sh.err 
 if [$? -NE 0] 
 then 
     cat /tmp/sh.err 
     Read -P "Please enter the Q/Q exit script." C 
     if [-z "$ c"]] 
     then 
         vim $ 1 
         exit 0 
     FI 
     if [$ c == q] || [$ c == 0] 
     then 
         exit 0 
     else 
         vim $ 1 
         exit 0 
     FI 
 else 
     echo "script $ 1 No grammar error" 
 FI

• 40. Formatal number

Demand:

• Input a string of random numbers, and then output by thousands of points
• For example, the input number string is “123456789” and the output is 123,456,789.

Core points:

• Like all the numbers, each number is stored in temporary files

[[email protected]~]# Cat 40.SH 
 #!/bin/bash 
 n =` Echo $ 1 | WC -L` 
 For d IN `echo $ 1 | SED 'S /./&//G' #. Represents numbers, & indicate the front. After adding spaces, you can output space between characters 
 DO 
     n2 = $ [$ n%3] 
     if [$ n2 -eq 0] 
     then 
         echo -n ", $ d" #echo -n, not printing and changing lines 
     else 
         echo -n "$ d" 
     FI 
     n = $ [$ n-1] 
 Done | SED 'S/^, //' 
 echo