shell scripting books

ENGINEER1.4Shell Script BasicsUnderstanding the shell environmentHow bash shells are usedInteractive:--manual intervention, high degree of intelligence----explain execution by article, low efficiencyNon-interactive:-Need to design in advance, the difficulty of intelligence is big;--Batch execution, high efficiency;-Easy to implement in the background and quietly;What is Shell

"! -name "DB"! -name "rtx*" ' ">>/shell/bAckup.logElseecho "' Date +%y%m%d ' Delete unsuccessful" >>/shell/backup.logFi# from Email adminMail-s "DataBackup" [email protected] If [$WEEK-ne 0];thenif [!-d/hddf/database/' Date +%y%m%d '];thenMkdir-p/hddf/database/' Date +%y%m%d 'mv/hddf/database/{*.bak,*. BAK}/hddf/database/' Date +%y%m%d '/FiElseecho "Today is Sunday no data backup" >>/

Getting Started with Shell scripting--NextThis article introduces the following: Logical operators (, | 、!、 ^), test commands, script execution procedures1. Logical operators(1) and short circuit andTrue, False1 0And:1 1 = 11 0 = 00 1 = 00 0 = 0For , if the left condition is false, the value of the right condition is also evaluated. Features as long as a false is assumed to be falseShort Circuit with:

=" wkiom1m89gsqup5laaayxllznls535.png "/> Execution Result: (believe that you know everything)650) this.width=650; "src=" Https://s1.51cto.com/wyfs02/M01/A5/69/wKioL1m89FHR3lnMAAArUD8lCS4739.png "title=" 99. PNG "alt=" Wkiol1m89fhr3lnmaaarud8lcs4739.png "/>Jump out of a single loop Continu statement:Continue [n]: End of the nth layer of the current cycle, and directly into the next round of judgment; the inner layer is the 1th floor.Come on, let's take an example:650) this.width=650; "src=" Http

Gzexe Help Shell Scripting Encryption onFirst, Introductionmany times our script will involve some private information, such as: User name, password, or other important information, we use some encryption to block this information, to ensure that the security of the system has been scripted, usually we only need to bring through the system's own Gzexe This tool is enough.Second, The experimental test b

TopicShell Scripting Knowledge points: What are trap signals in Linux system scripts and how are they used?Reference answer: "Trap signal Command description"The trap command is used to specify the actions to be taken after a signal is received, and a common use of the trap command is to complete the cleanup work when the script is interrupted.Historically, the shell always used numbers to represent the sig

The SED command usage for Shell Scripting Learning notesBasic usage of SEDSed:stream EditorLine EditorSED: Pattern space Stores matched text content in pattern spaceBy default, the original file is not edited, only the data in the pattern space is processed, and then, when the processing is finished, the contents of the schema mode space are displayedSed-N-I: Modify the original file directly-E script-e scr

big side.Listen to the old boy teacher and some experts said that the best way to learn early is to knock and break the problem of practice.The highest programming self-perception is:Problem analysis decomposition is fast and complete.Completeness: is to judge the various possibilities.High efficiency, high performance, 1+2+3...+100 = (1+100) * (100/2)/2Old boy Shell advanced programming combat Video 52 freeHttp://edu.51cto.com/course/course_id-963.h

file Content:bin:x:2:2:bin:/bin:/usr/sbin/nologin　　The done command is useful for looping the results of a loop to another command, redirecting to a file or screen, and using other commands to display to the screen[Email protected]:/data# cat Demo7 #!/bin/bashfor State in ' North Dakota ' Connecticut Illnois Alabama Tennesseedo Echo "$state is the next place to go" done | Sort > Textecho "This completes we travels" [email protected]:/data#./demo7 This completes our travels[email protecte

Bit left shift >> Bit right Shift Bit Boolean and | Bit Boolean or Logic and || Logical OR Code 2-11[Email protected]:/data# cat Demo3 #!/bin/bashval1=10if (($val 1 * * 2 >) then ((val2= $val 1 * * 2)] echo "The sq Uare of $val 1 is $val 2 "Fi[email protected]:/data#./demo3 the square of 100　　use both brackets[[Expression]] provides another feature

子这里定义一个全局变量hobby[[Email protected] ~]# exit #退出, go into Dad's bash environment[Email protected] ~]# echo $hobby #爹是看不到儿子的export的, son's son can seeJob Two: awk text processingPrint user names for UID within the 30~40 rangePrint the line number and user name of the 第5-10 linePrint odd linesPrint even rowsPrint a row with a number of fields greater than 5Print uid Not equal to GID usernamePrint a user without a shell specifiedJob Three:

Tags: shell multi-line redirection1. What is the problem requirement?First, the need to come from, mainly to write shell script, with cat for multi-line input redirection, the Terminator must be hyphenation first, the format is not good-looking.2, how? How to solve this problem?First Baidu, Google search the next, the result is to say that more is the shell multi

parameter$n is the nth parameter"[Email protected]" was expanded to "$" "$" "$" and so on.10. Use the child shell to generate a separate processThe child shell itself is an independent process. You can use the () operator to define a child shell:Pwd(CD/BIN;LS)PwdWhen executed in a child shell, there is no effect on the current

A goal is a dream with a deadline. Much effort, Much prosperity.Why Encrypt shell scripts? Of course it's for security!Maybe the script involves a password or something, and it needs to be encrypted.I. Download and install the SHC toolTo protect your own shell scripting program, there are many methods, the simplest way there are two: 1, encryption 2, set the expi

check if a string begins with the letter "abc"?[[$string = = abc*]][ [$string = = abc*]] and [[$string = = "abc*"]] What's the difference?[[$string = = abc*]]-Check whether the string starts with the letter ABC[[$string = = "abc"]]-check if the string is exactly equal to ABC54) How do I list user names that start with AB or XY?egrep "^ab|^xy"/etc/passwd|cut-d:-f1in bash) $! What does that mean?The PID of the recently executed command in the background.56) $? What does that mean?The end state of

Head> 3 title>Test Python Web servertitle>4 Head>5 Body>6This is a test Python Web server,b>Hello!b>7 Body>8 HTML>View CodeHistory |awk ' {cmd[$ 2]++; count++;}END {for (a in CMD) print cmd[A] "" cmd[a]/count* "%" A} ' |Grep-v "./" |Column-c3-s ""-t |Sort-nr |NL | Head-n10 This line of script can output your most commonly used 10 commands, so you can even insight into what kind of programmer you are. Do you know the code? It doesn't matter, the system learns * nix

Processing of parameter processing-shell incoming parameters $#The number of arguments passed to the script $*Displays all parameters passed to the script in a single string. Unlike positional variables, this option parameter can be more than 9 $$The current process ID number for the script to run $!Process ID number of the last process running in the background [emailprotected]With the $# same, but quoted when used, and retu

First, Background introductionDBA Daily Update Insert|update More, delay a lot of time. The development of tools, although the user password in the script encryption and strict operation, but carefully query internal logic or may reveal the password, today, using Gzexe method to encrypt the shell script.Second, start testing1. Find a test script to execute. (The online script content is inconvenient to publish, write the test script yourself.) ）　　2. E

contents):Real 3m41.864suser 0m34.224ssys 0m2.102sSo efficiency is barely acceptable.Test of Method Two:Time Awk-f awkfile datafileResults (omission of file contents):Real 2m26.487suser 0m7.044ssys 0m1.371sEfficiency is significantly better than the first one.Then examine the efficiency of method three:Time awk ' Begin{srand ()}{b[rand () nr]=$0}end{for (x in B) print b[x]} ' dataResults (omission of file contents):Real 0m49.195suser 0m5.318ssys 0m1.301sIt's pretty

/functionsport=3306User= "Root"Bindir= "/application/mysql/bin"Datadir= "/application/mysql/data"Mysqld_pid_file_path= "/application/mysql/' hostname '. pid"Path= "/sbin:/usr/sbin:/bin:/usr/bin: $basedir/bin"Export PATHReturn_value=0# Lock directory.Lockdir= '/var/lock/subsys 'Lock_file_path= "$lockdir/mysql"Log_success_msg () {echo "success! [Email protected] "}Log_failure_msg () {echo "error! [Email protected] "}Start () {# Start Daemonecho "Starting MySQL"If Test-x $bindir/mysqld_safeThen$bin