Shell Script
Written in Python, PHP scripts usually need to have a functional language, then you do not need Shell scripts, just need to know Linux commands can write Shell scripts, Shell scripts because Linux is composed of a plurality of commands, save by multiple Linux commands into a script file can be used directly to others.
A combination of command
Enter a directory, see directory of files, this process needs to execute two commands are, respectively cd, and ls.
Two separate forms of execution of the command is as follows:
[root@lincoding usr]# cd /usr/
[root@lincoding usr]#
[root@lincoding usr]# ls
bin etc games include lib lib64 libexec local sbin share src tmp
[root@lincoding usr]#We can use the semicolons ;to command the two together in combination, the order of execution, the execution of the form with the following:
[root@lincoding usr]# cd /usr/ ; ls
bin etc games include lib lib64 libexec local sbin share src tmp
[root@lincoding usr]#Shell script writing process
So if these two frequently used commands or provided to others to use, we can save these two commands together with Shell script file.
01 establish Shell script file
Use the bash Shell usually .shsuffix
[root@lincoding home]# touch test.sh02 Shell script writing
By vicommand to write test.sha script, reads as follows:
cd /usr/
lsNote that Shell script behind each statement without a semicolon ;, each command by way of wrap, Shell script execution time of the order will be executed.
Shell scripts execute permissions given 03
Because when building the file, the default is not authorized to perform, we need to give permission to execute the script, the script can run
[root@lincoding home]# chmod u+x test.shView Script Permissions
[root@lincoding home]# ls -l test.sh
-rwxr--r--. 1 root root 13 Sep 12 09:10 test.sh04 Shell script execution
Bash Shell script execution with the results of the implementation and results of our execution on the outside is the same one-line command combination
[root@lincoding home]# bash test.sh
bin etc games include lib lib64 libexec local sbin share src tmpShell statement interpreter
So here also consider other issues, assuming that Shell put this script will be a problem when running under a different system, if the system is not the default Shell bash, Shell execute this script may fail because there may be Some of the bash Shell properties in it.
Then we can at Shell script file first line declares it used to be which Shell, written in the following format:
#!/bin/bashThe benefits of this writing, the Shell script execution time, the system will automatically tell by bashShell interpreter to execute the script.
We will just test.sh script is modified as follows:
#!/bin/bash
cd /usr/
lsSo after which Shell statement using an interpreter, the way we execute scripts can become very simple
[root@lincoding home]# ./test.sh
bin etc games include lib lib64 libexec local sbin share src tmpsummary
When we write Shell scripts, the first line to be #!/bin/bashdeclared Shell interpreter, after writing to give Shell permission to execute, then you can perform the operation.