The shell practice of Linux Learning

The shell practice of Linux Learning

1. Describe the operation principle of shell program (can be attached with necessary graphic instructions);

2, summarize all the knowledge points involved in shell programming (such as: variables, grammar, command status, etc., to take the picture of Yo);

Summary article: http://pizimsn.blog.51cto.com/7002551/1697671

3, summarize the course of all the circular statement, the use of conditional judgment and related examples; (if (jpg|png is not exist); echo "You say a XX")

Summary article: http://pizimsn.blog.51cto.com/7002551/1698001

4. Summarize the usage of the Text Processing tool sed and awk (must accompany the example)

Summary article: http://pizimsn.blog.51cto.com/7002551/1698005

5. Write a script: If a path does not exist, it is created as a directory; otherwise it is present and the content type is displayed; (Don't doubt it's that simple)

[[email protected] ~]# Bash a.sh/root/test/This path is the presence of drwxr-xr-x. 2 root root 4096 September 20:58/root/test/[[email protected] ~]# cat a.sh#!/bin/bash# first row fixed # 5th determine if the path exists dirname= "/root/test/ "If [-e $dirname];then echo" $dirname This path is present in "Echo ' Ls-ld $dirname ' else mkdir-p $dirnamefi [[email protected] ~ ]#

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6, write a script to complete the following functions; Judging the given two values, which is the big or small; the method of the given number: script parameter, command interaction; (still so simple using read)

#!/bin/bash# First line fixed format # 6th determine the size of a given two number read-p "Please enter two number:"-t nu1 nu2if [$nu 1-gt $nu 2];then echo "$nu 1 greater than $nu 2" elif [$nu 1-lt $nu 2];then echo "$nu 1 less than $nu 2" elif [$nu 1-eq $nu 2];then echo "$nu 1 equals $nu 2" else echo "fi

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7, the sum of all the odd numbers within 100 (at least 3 methods. Yes, this is our assignment. ^_^)

#!/bin/bash# First line fixed format # 7th ask for 100 odd and let Sum=0for I in $ (SEQ 1 2);d o let sum=$[$sum + $i]doneecho $sum

#!/bin/bash# First line fixed format # 7th ask for 100 odd and Let Sum=0for ((I=1; i<=100;i++));d o if [$[$i%2]-eq 1];then let sum=$[$sum + $i] Fidoneecho $sum

#!/bin/bash# First line fixed format # 7th 100 odd and Declare-i sum=0declare-i i=1while [$i-le];d o if [$[$i%2]-ne 0];then Let sum+= $i fi let I++doneecho $sum

8, write a script to achieve the following functions:

(1) Pass two text file path to script;

(2) Show the number of blank lines in two files and their blank lines;

(3) Show the total number of files in two files and their total number of rows;

#!/bin/bash# First line Fixed # 8th, compare and count the blank lines of the two files passed if [ $# -lt 2 ];then         echo  "        exit 1fiif ["  $ (grep  "^$"  $1 | wc -l)  -gt $ (grep  "^$"  $2 | WC  -l)  ];then        echo  "More blank line  file is $1 " && echo " there are $ (grep  "^$"  $1  | wc -l)  blank lines "else        echo " more  blank line file is $2 " && echo " there are $ (grep   "^$"  $2 | wc -l)  blank lines "fiif [ $ (wc -l $1 |  cut -d " "  -f1)  -gt $ (wc -l $2 | cut -d " "  - F1)  ];then        echo  "More line is $1"  && echo  "File number: $ (wc -l $1)" else        echo  " More line is $2 " && echo " file number: $ (wc -l $2) " Fi

9. Write a script

(1) Prompt the user to enter a string;

(2) Judgment:

If the input is quit, exit the script;

Otherwise, the string content of its input is displayed;

#!/bin/bash# First line fixed format # 9th, prompted to enter a word, and then compare Read-p "Please enter a word:"-t wordif ["$word" = = ' quit '];then echo "you entered $word, Byeby   E! " Exit 10else echo "The word you typed $word not what I wanted" fi

10, write a script, print 2^n table; n equals the value entered by a user; (Sorry, I'm naughty)

#!/bin/bash# First line fixed format # 10th, print 2 of the N-square table Read-p "Please enter a number of times"-T Numlet sum=1for ((i=1; I <= "$num"; i++));d o let sum=$[$su M*2]doneecho "2^ $num = $sum"

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11, write a script, write a few functions: function 1, to achieve the sum of two numeric values, function 2, take a given two numeric value of greatest common divisor, function 3, take a given two numeric value of least common multiple; about the selection of functions, the size of two values will be provided through interactive input.

#!/bin/bash# First line fixed format # 11th read -p  "Please enter sum/gcd/lcm: "  -t 100 moderead -p  " Please enter two number: " -t 1000 nu1 nu2let sumnum=0function sum () {  let sumnum=$ [$nu 1+ $nu 2]  echo  "$nu 1 +  $nu 2  and is $sumnum"}LET GCDNUM=0FUNCTION GCD () {  c=$[$nu 1% $nu 2] while [  "$c"  -NE 0 ];d o  let gcdnum= $c    nu1= $nu 2  nu2= $c   c=$[$nu 1% $nu 2] doneecho  $gcdnum}let lcmnum= 0FUNCTION LCM () {  c=$[$nu 1% $nu 2] pro=$[$nu 1* $nu 2]while [  "$c"  -ne 0 &NBSP,];d o tmp= $c  nu1= $nu 2 nu2= $c  c=$ ((nu1%nu2)) done let lcmnum=$[$pro/$tmp]echo   "$lcmnum"}if [  "$mode"  ==  "sum"  ];then    sum  $nu 1   $nu 2elif [  "$mode"  ==  "GCD"  ];then    gcd  $nu 1 $ nu2elif [  "$mode" == " LCM " ];then   lcm  $nu 1  $nu 2else  echo " Your input is wrong! "Fi

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The shell practice of Linux Learning