best book to learn unix shell scripting

1, #!/bin/shThe first line tells the operating system that the interpreter for this script is/bin/sh this executable file2. While loop:#!/bin/shSleep 1; echo "User"; \Sleep 1; echo "Password"; \While true; Do \echo "Output"Sleep 1; \Done3, the shell script realizes the automatic input of Telnet, implements with the pipeline, the last while loop is used to give the last command full execution time(Sleep 1; echo "user"; \Sleep 1; echo "Password"; \Sleep

Break is to jump out of the current loop, and continue is to jump out of the loop and start the new loop again[Email protected] test]#CatDemo.SH #/bin/Bash while true; DoRead-P"Please input number:"x yif((x>9)); ThenContinueelif((y>9)); Then BreakElseZ=$ ((x+y))Echo$zfi DoneEcho "Execution completed!"[email protected] test]#SHDemo.SHPlease input number:1 23Please input number:Ten 2 # $x >9, when the back part of the secondary loop is not executing, and the loop starts againPlease input number

Tags: meaning cond centos7 test cat size pre BER syntax errorNote: The comparison string in the shell can only be used = =, Compare numbers using-eq,-ne,-gt,-ge,-lt,-le, or = =, [[Email protected]SH]$CatNumber_compare.SH #!/bin/bash# script Name: Number_compare.SH#用途: Compare two digit sizesEcho "Please input first number :"Read xEcho "You first number x= $x"Read-P"Please input second number:"yEcho "You second number y= $y"if[$x-eq $y]; Then Echo

command. You can use Echo to print any variable value in any place where you suspect it is wrong. That's why most shell programmers spend 80% of their time debugging programs. of the Shell programThe advantage is that there is no need to recompile, and it does not take much time to insert an echo command.The shell also has a real debug mode. If there is an error

results of "mail.jpg tux.jpg".quotation marks (single and double quotation marks) prevent this wildcard extension: #!/bin/shecho "*.jpg" Echo ' *.jpg ' This will print "*.jpg" two times.Single quotes are more restrictive. It prevents any variable expansion. Double quotes prevent wildcard expansion but allow variable expansion. #!/bin/shecho $SHELLecho "$SHELL" Echo ' $SHELL ' The result of the operation is

Today, let's learn about Common Unix shell commands. We all know that Unix shell is not only a user interaction interface, but alsoProgramDesign Language: when the system registers, it will execute a Unix

seconds, in the shell script of the usual term loop.At this point, you press CTRL +z to pause it, and then enter BG to go back into the background.In the case of multitasking, if you want to move the task to the foreground, FG is followed by the task number and the task number can be obtained using the jobs command.9. >>, 2>, 2>> : The above-mentioned directional symbols > and >> denote the meaning of substitution and addition, then there are two sym