linux shell

Arithmetic operations are essential in any programming language, and the shell is no exception. First, use Let, (()) and [] for arithmetic operations You can use the normal variable assignment method to define a numeric value, which is that it will be saved as a string. We can use Let, (()), [] and other operators to make these variables to perform arithmetic operations. For example: Copy Code code as follows: #!/bin/bash No1=4 #此处no1义字符

To ensure that the PHP page runs in the background, write a monitoring script, assuming that the program exits unexpectedly, you can automatically restart. Shell Script/usr/local/scripts/receve.sh content: #!/bin/bash #funtion: Keep receve.php running php= "/usr/local/php5/bin/php" program= "receve.php" #start Dameo $PHP/home/httpd/$PROGRAM >>/usr/local/scripts/phpshell/receve.out chpid= "$!"; echo "$chpid" >/usr/local/scripts/phpshell/recev

Example of a bash case statement. Sharing a bash shell code is helpful in understanding the use of case statements by students who learn about bash. Example: Copy Code code as follows: #!/bin/bash ## # program: # File operation # 1.) Open file 2.) Display file 3.) Edit file 4.) Delete file # Site:WWW.JB51.NET Path=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin Export PATH echo "-------------------

1. Read command The read command reads information through a keyboard or a line of text in a file and assigns a value to a variable. 1.1, read reading the keyboard data, the input of the content before the return of the data assigned to a variable: cb@standalone14:~$ read name Hello CB I am ubuntu. #回车 cb@standalone14:~$ echo $name Hello CB I am ubuntu. #显示变量的值1.2, instance shell script, save code as. sh file, change executable permissions, run

between the two please check the relevant information of environment variables Explain: \e[32;1m: This is the escape character that controls the font and background color, 30~37 is the font color, 40~47 is the background color The position of the 32;1m number in the example can be reversed as \e[1;32m, if it is in the X environment can be replaced 1 of the range 0~10, may have no use: 0 or do not write (\e [0;32m or \e[;32m) display light color, 1: Show highlights 4: underlined ... If the effec

Each process will have a PID, and each PID will have a corresponding directory under the/proc directory, which is the implementation of Linux (current kernel 2.6) system.General backdoor procedures, in the PS and other processes to see the tool can not be found, because these common tools and even the system library in the system after the invasion has been basically passive hands and feet (the internet spread a large number of rootkit. If it is a ker

A: This script runs the machine, LinuxB: The machine that installs the JDK, Linux First, on machine A on which the script runs, determine that you can log on to machine B on the JDK by SSH without a password, and then you can run this script on a: Copy Code code as follows: $./install-jdk.sh B's IP Or Copy Code code as follows: $./install-jdk.sh "B's IP" "JDK's uri" You can install the JDK on machin

This is also a document comparison command, and mastering will save you a lot of work. Do you remember the comm order? Diff is more complex than he is, easy to use, not only to compare files, but also to compare directories. When a file has multiple versions, or more complex files, and directory comparisons, you expect a command that is more useful than Comm, and the diff is born for it. Full Name: Different file Instance: File 1:v1.txt Copy Code code as follows: Hello Worl

In the hint: many of the translation of Ubuntu is literal literal translation, there are many problems, so I suggest you refer to my explanation here. Of course, it was also some of the suspicion of the text, I hope. Often operate on Linux, have a few fixed commands in different directories, or modify a few fixed files, this time, if you can operate them in a directory, it will be a very easy thing. Let's take a look at the link command Ln Name The

1. "" "" "The Difference," "The variables will be resolved" "All of them as strings" "to execute system commands 2. The custom variable defaults to a local variable, and the environment variable is a global variable. 3.export can set one or more variables as global variables 4. To use a variable in a child shell in the parent shell, you must set the variable to global with export 5. Commonly used enviro