linux containers explained

] [+ |-| =] [mode] file name?Action object who is either or their combination of the following letters:U means "user", which is the owner of the file or directory.G means "same group user", that is, all users with the same group ID as the file owner.O means "other (others) users".A means "all users". He is the system default value.+ Add a permission.-Cancels a permission.= gives the given permission and cancels all other permissions, if any.Setting the permissions represented by mode can be any

File types in LinuxIn a Linux system, you can say that everything is fileThe role of extensions under Linux1). Tar,. tar.gz,. tgz,. zip,. tar.bz represent compressed files, and create commands typically tar, zip, gzip, and so on2). SH represents a shell script file, a program developed through the shell language3). pl represents Perl language files, programs developed in Perl language4). py represents Python language files, programs developed in Pyth

Remember that in the previous introduction of the C H o d command, the permissions bits and files of the directory are different. Now let's take a look at the difference. The Read permission bit for a directory means that the contents can be listed. The Write permission bit means that you can create files in this directory, and you can cancel the corresponding write permission bits if you do not want other users to create files in your directory. Executing a permission bit means searching for an

It's mainly about rsync.On-Machine experimentand write some scripts.Here is the script for automatic backup#bak Site and logscd/var/html tar zcf/backup/www_$ (date +%f). tar.gz./wwwCd/app tar zcf/backup/logs_$ (date +%f). tar.gz./logs#bak SYS confCD/ tar zcf/backup/etc_$ (date +%f). tar.gz./scripts/bin/cp/var/spool/cron/root/backup/#rsync data to BakserverRsync-avzp/backup/rsync [Email protected]::backup/--password-file=/etc/Rsync.password#del data 7 days agoFind/backup-type f-name "*.tar.gz"-

, function 1 content (first part), lock, function 2 contents, unlock, Function 1 contents (Part Two), unlock.If the contents of function 1 are not reentrant, and function 2 modifies the operand of function 1, there will be a problem here.Like what. The function 1 is to get the sum of the global int array (set to int a[4] = {1,2,3,4}), the first part is for the first half, and the second part is for the last half part.And if the function 2 causes the int array to change, for example lets a[2] = 0