Thank you---------Linux Bash programming

Array

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M00/A5/27/wKioL1m4vYHidlQVAAA4SIobYQM360.png "title=" Qq20170913130915.png "alt=" Wkiol1m4vyhidlqvaaa4siobyqm360.png "/>

Array name

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/A5/27/wKioL1m4vcjgjKBsAAAWDCiEdu0044.png "title=" Qq20170913131032.png "alt=" Wkiol1m4vcjgjkbsaaawdciedu0044.png "/>

Array definition

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M00/A5/27/wKioL1m4vnmhNRQYAAAqYzc8dBI109.png "title=" Qq20170913131327.png "alt=" Wkiol1m4vnmhnrqyaaaqyzc8dbi109.png "/>

Array reference

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M01/A5/27/wKioL1m4vumy5DHGAAAOQaM2cH0019.png "style=" float : none; "title=" Qq20170913131516.png "alt=" Wkiol1m4vumy5dhgaaaoqam2ch0019.png "/>

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M01/06/77/wKiom1m4vxKTZ3QWAAAPXO4WFLc688.png "title=" Qq20170913131458.png "style=" Float:none; "alt=" Wkiom1m4vxktz3qwaaapxo4wflc688.png "/>

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M02/A5/27/wKioL1m4vyDzyJvxAAAQZnkOBjA629.png "style=" float : none; "title=" Qq20170913131550.png "alt=" Wkiol1m4vydzyjvxaaaqznkobja629.png "/>

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M02/06/77/wKiom1m4v3DwIzhOAAANVLkGOoU152.png "title=" Qq20170913131654.png "alt=" Wkiom1m4v3dwizhoaaanvlkgoou152.png "/>

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M00/06/77/wKiom1m4v0qDay9NAAAPWdRj_XQ262.png "style=" float : none; "title=" Qq20170913131555.png "alt=" Wkiom1m4v0qday9naaapwdrj_xq262.png "/>

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M02/A5/27/wKioL1m4v3vg-pkTAAAQa-QshRk862.png "title=" Qq20170913131747.png "alt=" Wkiol1m4v3vg-pktaaaqa-qshrk862.png "/>

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M02/A5/27/wKioL1m4vyGhOz6GAAAe0UWV24Q660.png "style=" float : none; "title=" Qq20170913131602.png "alt=" Wkiol1m4vyghoz6gaaae0uwv24q660.png "/>

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M01/06/77/wKiom1m4v0rDJhgbAAAZhuWIT8E599.png "style=" float : none; "title=" Qq20170913131612.png "alt=" Wkiom1m4v0rdjhgbaaazhuwit8e599.png "/>

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M01/06/77/wKiom1m4wAzSYDjhAAAU2PjbwvQ807.png "style=" float : none; "title=" Qq20170913131923.png "alt=" Wkiom1m4wazsydjhaaau2pjbwvq807.png "/>

How array elements are assigned

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/A5/27/wKioL1m4wa-C9uAVAAATBtnM1ZU581.png "style=" float : none; "title=" Qq20170913132633.png "alt=" Wkiol1m4wa-c9uavaaatbtnm1zu581.png "/>

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M01/A5/27/wKioL1m4wa_CHY3zAAAqTlLmvZw375.png "style=" float : none; "title=" Qq20170913132642.png "alt=" Wkiol1m4wa_chy3zaaaqtllmvzw375.png "/>

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M02/06/77/wKiom1m4wdjyfqtEAAAslo_Y7L0656.png "style=" float : none; "title=" Qq20170913132650.png "alt=" Wkiom1m4wdjyfqteaaaslo_y7l0656.png "/>

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M02/A5/27/wKioL1m4wfzjqZjkAAAzRhbbzH0252.png "title=" Qq20170913132823.png "alt=" Wkiol1m4wfzjqzjkaaazrhbbzh0252.png "/>

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M02/A5/27/wKioL1m4wbCweTH1AAAbLLzd3R0606.png "style=" float : none; "title=" Qq20170913132705.png "alt=" Wkiol1m4wbcweth1aaabllzd3r0606.png "/>

Destroying an array

Unset Array_name[index]

Exercise: Generate 10 random numbers to save in an array, take out the maximum and minimum values

Exercise: Generate 10 random numbers in an array, and find the sum of all random numbers labeled even

Exercise: Write a script to define an array in which the elements in the array are all filenames ending in. Log in the/var/log directory, and the sum of the number of rows in the file to be labeled even

Exercise: Generate 10 random numbers, sort them

Example one: Generate 10 random numbers saved in the array, take out the maximum and minimum values #!/bin/bash#declare-a randdeclare-i max=declare-i min=for i in {0..9}; dorand[$i]= $RANDOMecho ${rand[$i]}if [$i-eq 0]; thenmax=${rand[$i]}min= $maxfiif [$max-lt ${rand[$i]}]; thenmax=${rand[$i]}fiif [$min-gt ${rand[$i]}]; thenmin=${rand[$i]}fidoneecho "Max: $max" echo "min: $min"

Example one: Generate 10 random numbers saved in an array, and the sum of all random numbers labeled as even is #!/bin/bash#declare-a randdeclare-i sum=0for i in {0..9}; dorand[$i]= $RANDOMecho ${rand[$i]}if [$[$i%2]-eq 0]; Thenlet sum+=${rand[$i]}fidoneecho "sum: $sum"

Exercise: Write a script to define an array in which the elements in the array are all file names ending with. Log in the/var/log directory, and the sum of the number of rows in the file whose subscript is even is counted #!/bin/bash#declare-a file_namefile_name= (/var  /log/*.log) # # array_name= ("Val1" "Val2" "Val3" ...) only a space in Val is necessary to write quotes Declare-i sum=0for i in $ (seq 0 ${#file_name [@]}); Dolet i-=1if [$[$i%2]-eq 0]; thensum=$[sum+$ (Wc-l < ${file_name[$i]})]fidoneecho $sum

Exercise: Generate 10 random numbers, sort them #!/bin/bash#declare-a randdeclare-i i=0while [$i-le 9]; dorand[$i]= $RANDOMlet i++doneecho "${rand[@]}" | Xargs-n 1 | Sort-n-R | Xargs

Character slices

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M02/A5/28/wKioL1m4x8_QZFC-AAAykzgA-OU765.png "title=" Qq20170913135311.png "alt=" Wkiol1m4x8_qzfc-aaaykzga-ou765.png "/>

To take a substring based on a pattern

From left to right #*string ##*string

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M02/06/77/wKiom1m4yGDQOYI0AAAItJ2J33I333.png "style=" float : none; "title=" Qq20170913135454.png "alt=" Wkiom1m4ygdqoyi0aaaitj2j33i333.png "/>

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/06/77/wKiom1m4yQ_R6cpSAAAK_sgg-d0294.png "style=" float : none; "title=" Qq20170913135742.png "alt=" Wkiom1m4yq_r6cpsaaak_sgg-d0294.png "/>

From right to left%string*%%string*

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/A5/28/wKioL1m4yOaTYriLAAALQJV7H6A515.png "style=" float : none; "title=" Qq20170913135749.png "alt=" Wkiol1m4yoatyrilaaalqjv7h6a515.png "/>

650) this.width=650; "src=" Https://s2.51cto.com/wyfs02/M02/A5/28/wKioL1m4yLCDVPYhAAAIw5cRuzs618.png "style=" float : none; "title=" Qq20170913135656.png "alt=" Wkiol1m4ylcdvpyhaaaiw5cruzs618.png "/>

Find replacement <[line header, tail] characters >

Replace with character, from left to right

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M02/06/78/wKiom1m4yxWRepCCAABAR2yYi_Q163.png "title=" Qq20170913140634.png "alt=" Wkiom1m4yxwrepccaabar2yyi_q163.png "/>

Replace with an empty

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M00/06/78/wKiom1m4yzjRR-SbAAAG545z9jg858.png "title=" Qq20170913140711.png "alt=" Wkiom1m4yzjrr-sbaaag545z9jg858.png "/>

Using the example

650) this.width=650; "src=" Https://s3.51cto.com/wyfs02/M00/06/78/wKiom1m4zMWRAZEiAABZ8xr3ANA360.png "title=" Qq20170913141344.png "alt=" Wkiom1m4zmwrazeiaabz8xr3ana360.png "/>

character-Case conversions equivalent to TR ' A-Z ' A-Z

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/A5/28/wKioL1m4zLii-OkrAAANM5mFJOc703.png "title=" Qq20170913141415.png "alt=" Wkiol1m4zlii-okraaanm5mfjoc703.png "/>

Using the example

650) this.width=650; "src=" Https://s2.51cto.com/wyfs02/M00/A5/29/wKioL1m4zS6jlfgrAAAOCVz637I327.png "title=" Qq20170913141612.png "alt=" Wkiol1m4zs6jlfgraaaocvz637i327.png "/>

variable Default value

Not present, assignment

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/06/78/wKiom1m4zsjBtggNAAAtc-V3JMQ795.png "style=" float : none; "title=" Qq20170913142202.png "alt=" Wkiom1m4zsjbtggnaaatc-v3jmq795.png "/>

650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/A5/29/wKioL1m4zp-R4IVCAAAplI9fupQ453.png "style=" float : none; "title=" Qq20170913142215.png "alt=" Wkiol1m4zp-r4ivcaaapli9fupq453.png "/>

Is present, the value is assigned

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M01/A5/29/wKioL1m4zvmD51p2AAAk60EyLIk592.png "title=" Qq20170913142352.png "alt=" Wkiol1m4zvmd51p2aaak60eylik592.png "/>

There is no error, there is a return var

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M01/06/79/wKiom1m4z5-i_nYBAAAN_ioENH0579.png "title=" Qq20170913142555.png "alt=" Wkiom1m4z5-i_nybaaan_ioenh0579.png "/>

Providing configuration for scripts

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M01/A5/29/wKioL1m40HGDF47tAAAXFjkmjLw201.png "title=" Qq20170913143007.png "alt=" Wkiol1m40hgdf47taaaxfjkmjlw201.png "/>

Use example: To set the host name

650) this.width=650; "src=" Https://s4.51cto.com/wyfs02/M02/A5/29/wKioL1m40TPB96AMAAAR3Tk9gds160.png "title=" Qq20170913143315.png "alt=" Wkiol1m40tpb96amaaar3tk9gds160.png "/>

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M02/06/79/wKiom1m40YXzaj_6AAAc6baEPOw562.png "title=" Qq20170913143403.png "alt=" Wkiom1m40yxzaj_6aaac6baepow562.png "/>

Mkstemp command

650) this.width=650; "src=" Https://s5.51cto.com/wyfs02/M01/A5/29/wKioL1m40iPidPO9AABHRl7jVzo074.png "title=" Qq20170913143721.png "alt=" Wkiol1m40ipidpo9aabhrl7jvzo074.png "/>

Install command

650) this.width=650; "src=" Https://s2.51cto.com/wyfs02/M02/A5/29/wKioL1m40weiCYzSAAA7DJkG3cs033.png "title=" Qq20170913144110.png "alt=" Wkiol1m40weicyzsaaa7djkg3cs033.png "/>

Exercise: Write a script

1) Prompt the user to enter the name of an executable command

2) Get a list of all library files that this command depends on

3) Copy the command to a target directory (for example,/mnt/sysroot) under the corresponding path,

/bin/bash-/mnt/sysroot/bin/bash

/USR/BIN/PASSWD-/MNT/SYSROOT/BIN/PASSWD

4) Copy all the library files that this command relies on to the corresponding path under the target directory

/lib/ld-linux-x86_64.so.2-/mnt/sysroot/lib/ld-linux-x86_64.so.2

Further to:

Each time a copy completes a command without exiting, it prompts the user to type the new command to be copied and repeats the above function until the user enters quit

#!/bin/bash# version: 0.0.15# author: lcc.org# description:&nbsp, ..... Dir= "/mnt/sysroot" [ -d  $DIR  ] | |  install -d  $DIRfunction  cpcmd {cmd_path=$ (which --skip-alias $1) Local  cmdir=$ (echo  $cmd _path | sed  ' s,/$,, '  | sed -r  ' [email  Protected] (. */) ([^/]+) @\[email protected] ') [ -d  $DIR $cmdir ] | |  install -d  $DIR $cmdir[ -f  $DIR $cmd_path ] && echo -e   "\033[32m$dir$cmd_path\033[0m is exist"  | |  cp  $cmd _path   $DIR $cmd_path }function cp_lib {for i in $ ( ldd  $cmd _path | grep -o --color=auto  "/.*[[:space:]"  | tr -d   '   ');  dolocal libdir=$ (echo  $i  | sed  ' s,/$,, '  | sed -r   ' [email protected] (. */) ([^/]+) @\[email protecteD] ') [ -d  $DIR $libdir ] | |  install -d  $DIR $libdir[ -f  $DIR $i ] && echo -e  "\ 033[32m$dir$i\033[0m is exist " | |  cp  $i   $DIR $idone}read -t 10 -p  ' Enter a binary program  name:  '  fukewhile [  $fuke  !=  ' quit '  ]; doif [  ' $fuke  ==  "Quit"  -o -z  "$fuke"  ]; thencontinueelif ! which  $fuke  &> /dev/null; thencontinuefi# #复制命令cpCmd   $fuke # #复制库文件cp_lib # #显示复制完成echo  -E   "\033[32mcopy finished.....\033[0m" read -t 10 -p  ' enter again a  binary program name:  '  fukedone

This article is from the "Reading" blog, make sure to keep this source http://sonlich.blog.51cto.com/12825953/1964938

Thank you---------Linux Bash programming