linux shell scripting cookbook

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

.2) read uses the IFS character to parse the text, and here we specify the IFS as a comma.Cat >> $outfile This includes an output append redirect (>>) and an input append redirect (>> appends the output of the cat command to the file specified by the $outfile variable.The input to the Cat command is not taken from standard input, but is redirected to the data stored in the script.The EOF symbol marks the beginning and end of the data appended to the file.Input file + run + Result:DescriptionSpe

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

specified shell command V Start the VI editor with the current file . Repeat the previous command N Find in file the overflow matches the content of the specified expression ‘ Jumps to the first content that the specified expression matches to Ctrl+l Redraw the current scre

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

1. After opening the terminal prompt, $ represents a normal user, #表示管理员用户root, root is the most privileged user in the Linux system.2. A shell script is usually a text file with a #! start, where #! precedes the interpreter path. Example: #!/bin/bash3. Note section starts with #, and consistently continues to the end of the line4. By default, Echo adds a line break after each call. The text after echo can

The remaining space is Morethan the%, the message is sent to the Wl#tue2 the: $: AboutCst .PATH=/usr/local/bin:/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/wl/Binexport PATH forRemainingspaceinch$(DF-H |awk '{print $}'|grep-V' Use'|sed-E's/[%]//g') Do if[[$RemainingSpace > the]]; Then Echo-E"$RemainingSpace" Echo-E"$ (df-h | grep $RemainingSpace)">/service/script/. Harddiskwarning Mail-S"Disk Warning"WL . Harddiskwarningfi Done4. Detecting remaining Inode#!/bin/Bash#inspcet Inode

] ~]# vim/root/foo.sh#!/bin/bashIf ["$" = "Redhat"]Thenecho "Fedora"elif ["$" = "Fedora"]Thenecho "Redhat"Elseecho "/root/foo.sh Redhat|fedora" >2Fi2) Add x Execute Permissions[Email protected] ~]# chmod +x/root/foo.shStep two: Test foo.sh judgment Script1) test conditions that provide the correct parameters[Email protected] ~]#/root/foo.sh redhat Fedora[Email protected] ~]#/root/foo.sh Fedora Redhat2) test to provide unexpected parameters[Email protected] ~]#/root/foo.sh Ubuntu/root/foo.sh Redh

Linux shell scripting:1. Program Structure Exercise: Write a script, given a positive integer, to calculate the sum of all digits of this number.For example, if the program is given input 123, it should return 1+2+3=6.2. Program Structure Exercise: Write a script, given a positive integer, to output this number in reverse order.For example: program input 123, the

Write a script:1. Add 10 users user1 to User10, password with user name, but only if the user does not exist to add;#!/bin/bash# forIinch{1..Ten}; Do if!IDUser$i >/dev/NULL; ThenUseradd user$iEcho "user$i"|passwd--stdin user$iElse Echo "User$i exists" fi DoneDelete the above 10 users#!/bin/bash# forIinch{1..Ten}; Do if IDUser$i >/dev/NULL; ThenUserdel-r user$i >/dev/nullEcho "user$i deleted" Else Echo "user$i NOT EXISTS" fi DoneExtension: Adds or deletes a specif

) # #开启虚拟机echo Start VM ...Virsh Start $ >/dev/nullEcho Start VM $ successful!!!;;View) # #显示虚拟机Echo View VM ...Virt-viewer $ >/dev/nullEcho View VM $ successful!!!;;Stop) # #关闭/Stop virtual machineecho Stop VM ...Virsh Destroy $ >/dev/nullEcho VM $ is stopped!!!;;Reset) # #重置虚拟机echo Reset VM ...Virsh Destroy $ >/dev/nullVirsh Undefine $ >/dev/nullRm-fr/var/lib/libvirt/images/$2node.qcow2 # #删除原磁盘快照文件Qemu-img create-f qcow2-b/var/lib/libvirt/images/$2.qcow2/var/lib/libvirt/images/$2node.qcow2 >/

script requires a user name list file as a parameter2) If no parameters are provided, this script should give a hintUsage:/root/batchusers, exit and return the corresponding value3) If a nonexistent file is provided, this script should give aShow Input file not found, exit and return the corresponding value4) New User login Shell is/bin/false, no need to set password5) User list test file:Http://classroom/pub/materials/userlist# wgethttp://classroom/

Overview:Overview:This section describes the array of shell scripting in Linux, advanced string processing, advanced variables, and configuring the user's environment.One, function and positional parameter extension1. TheShift command implements the jump in the position parameter, which squeezes the leftmost parameter650) this.width=650; "src=" Http://s1.51cto.co

-nand 11 use, tell read command to accept single word specifier exitCode 2-25[Email protected]:/data# cat Demo5 #!/bin/bashread-n1-p "Do you want to continue [y/n]" Answercase $answer in y|y) E Cho echo "fine,continue on ...";; N|n) echo echo "Ok,goodbye" exit;; Esacecho "This is the end of the script" [email protected]:/data#./demo5 does you want to continue [y/n]yfine,continue on]. . This is the end of the script　　Hidden mode read, the-S optio

spaces. If IFS is null, the parameters is joined without intervening separators.oldifs= "$IFS" ifs= "" array= ($result) ifs= "$oldIFS" for I in ${array[@]}; Doecho $idone# Use Facter to get a set of Key-value# Facter output has a newline character, you must replace the newline character with a space# Replace newline characters with spaces to use awk or sed# awk-v rs= "" ' {gsub ("\ n", "");p rint} '# ECHO-E "2 \n1" | Sed ': A; n;$!ba;s/\n//g 'result=$ (facter | awk '/ipaddress/!/ipaddress_lo/{p

In Linux systems, the two most important files for user account management are/etc/password and/etc/shadow.In the/etc/password file, each line represents an account, but there are many accounts that are system accounts. Like what:Bin, ADM, etc., as well as administrator account root. The rest is for general user accounts.Each line is composed of (to: Split):1 account name;2 password (combined with/etc/shadow);3 UID User ID, where 0 is the root, 1~499

2017 09:48:22 +0800from localhost [127.0.0.1]-----The following addresses had permanent fatal errors-----[email protected]>(reason:550 Failed to connect remote host.)-----Transcript of Session follows-----... while talking to mx3.qq.com.:... while talking to mx2.qq.com.:So the machine was restarted a bit. You can do it.[Email protected]:/var/mail$ Echo]20171204tete" | Mail-s "TEst2"Xcy[Email protected]:/var/mail$ Mail"/var/mail/xcy": 3 messages 1 new 2 unreadU 1 Mail Delivery Subs December 4 10

]:~/learn$ cat Args.txt | Xargs SH cecho.sh;Arg1 arg2 arg3#Requirement 3, how do I embed parameters in a fixed command line? As shown below:Copy CodeThe code is as follows:[Email protected]:~/learn$ sh cecho.sh-p args1-1-P args1-1#[Email protected]:~/learn$ sh cecho.sh-p args2-1-P args2-1#[Email protected]sli-pc:~/learn$ sh cecho.sh-p args3-1-P args3-1#Solutions for using Xargs:Copy CodeThe code is as follows:[Email protected]:~/learn$ cat Args.txt | xargs-i {} sh cecho.sh-p {}-1-P arg1-1#-P arg

updated successfully.Changing password for user bruce03.Passwd:all authentication tokens updated successfully.Changing password for user bruce04.Passwd:all authentication tokens updated successfully.Changing password for user bruce05.Passwd:all authentication tokens updated successfully.Changing password for user bruce06.Passwd:all authentication tokens updated successfully.Changing password for user bruce07.Passwd:all authentication tokens updated successfully.Changing password for user bruce0

No orders found. 128 Invalid exit parameter 128+x Critical error for Linux signal x 130 Command terminated with CTRL + C 255 Exit status code out of bounds Exit Exit command can specify exit status code, but not more than 255, otherwise it will be moduloCode 1-16[Email protected]:/data# cat Demo4 #!/bin/bashdateecho $?whoexit 5[email protected]:/data#./dem