Learning "Linux in respect of such a study," notes quiz Lesson
Instructor: Liu Trent
fourth single vim editor with the SHELL command script
4.3.3 while condition loop
while condition loop is a way for the script based on certain conditions repeat the command statements, it determines the number of cyclic structures is often not performed before performing the final, completely different from the for loop statement target, has a range of usage scenarios. while loop to decide whether to continue to execute commands through testing to determine the conditions of true and false, if the condition is true to proceed, is false to end the cycle.
4.3.4 case statement conditional test
case statement is matched in multiple data range, if the match is successful implementation of the relevant commands and end of the whole test condition; and if the data is not within the range listed, will be to execute an asterisk (* ) as defined in the default command.
4.4 Scheduled Tasks service program
sharing command day Monday
Chapter 5 user identity and file permissions
5.1 user identity and capabilities
1, administrator UID 0: the system administrator user.
2, the system user UID is 1 ~ 999: Linux system in order to avoid a loophole in a service program is to provide the right to hackers entire server, the default service program will be responsible for running the stand-alone system users, thus effectively control the extent of damage.
3, the average user UID from the beginning of 1000: the user is created by the administrator for daily work.
5.1.1 useradd command, groupadd command, usermod command, passwd command, userdel command.
5.2 file permissions and ownership
