White space is important! Some symbols around need the blank space key separated, some can't add Spaces, the program runs problems first code second look at Spaces, run the program always greet today error, after baidu to is less a JDK in the virtual machine file, download the tub or useless, then with the help of the students found the original shell code # comments cannot be used in the beginning, perhaps because the beginning is to use #!/bin/bash, in addition to start can be used in other parts of the following is today's learning records:
1, write a named iffile program, it is executed judgment/bin directory under the date file exists? 2, write a greeting program, called the greet execution can be based on the current system time when greeting user output information, from midnight to noon in the morning, noon to 6 PM for the afternoon, at 6 PM until midnight for the night, 3, write a program, called ifuser it performs with user name as a command-line argument, determine whether the user has the login in the system, and provide relevant information, 4, write a program called menu to implement a simple popup menu function, the user can choose according to display a menu item from the keyboard to perform the corresponding command, 5, write a program, called chname will all the current directory. TXT file renamed. Doc files, 6, and write a program named chuser, the execution of every 5 minutes to check if the specified user login system, the user name from the command line input; If the specified user is logged in, show relevant information,