megabytes to gigabytes

The Java language provides eight basic types. Six types of numbers (four integers, two floating-point types), one character type, and one Boolean type.1, integers: including int,short,byte,long2. Float Type: float,double3, Character: Char4, Boolean: Boolean Basic type Size Minimum value Maximum Value Boolean 1-bit ----- ------ Char 16-bit Unicode 0 Unicode 2^16-1 Byte 8-bit -128

The free command displays the idle, easy-to-use physical memory and swap memory in the Linux system, as well as the buffer used by the kernel. In Linux system monitoring tools, the free command is one of the most frequently used commands.1. Command format:free [parameters]2. Command function:The free command displays system usage and idle memory conditions, including physical memory, interactive area memory (swap), and kernel buffer memory, and shared memory is ignored3. Command parameters:-B Di

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Find. -type f-size 100c-print # Check file length 100cFind. -type f-size +10-print #查长度超过期作废10块的文件 (1 block = 512 bytes)Find. -type f-size +2k #搜索当前目录下大于2KB的文件Find. -type f-size-2k #搜索当前目录下小于2KB的文件In addition to kilobytes (k), there are blocks (b 512 bytes), bytes (c), Word (w), megabytes (M), and gigabytes (G)based on operation time:Find/-type f-amin-10 #查找在系统中最后10分钟访问的文件Find/-type f-atime-2 #查找在系统中最后48小时访

-maxdepth and-mindepth should appear as the third parameter of find, assuming that as a fourth or later occurrence, it might affect the efficiency of find, because it has to do some unnecessary checking. ? ? 6). Search-type based on file type?? ? find. -type D-print #仅仅列出全部的文件夹?? ??? ? find.-type f-print #仅仅列出全部的文件?? ? find. -type L-print #仅仅列出全部的链接? 7). Search for-mtime (change time)-atime (time to visit) by file time-ctime (time of variation), time with +,-to indicate before and after time?? ?

:18./.viminfo-RW-------. 1 root root 1087 6? 21:14./anaconda-ks.cfg[Email protected] ~]#Find by File size　　-size [-/+]n' B ' for 512-byte blocks (the "the default if no suffix is used)' C ' for bytes' W ' for two-byte words' K ' for kilobytes (units of 1024x768 bytes)' M ' for megabytes (units of 1048576 bytes)' G ' for gigabytes (units of 1073741824 bytes)[Email protected] ~]# find-size +20000c [[email

, SwapoffTo view the memory space usage status:# Cat/proc/meminfo# free -M: Display results in megabytes -G: Display results in gigabytes [email protected] boot]# free-mTotal used free shared buffers CachedMEM:1006 350 655 0 89 222-/+ buffers/cache:39 966swap:815 0 815Note: Buffers is a buffer that improves write performance; Cached is a cache that improves read performance.DD command: Can copy, can detect

efficiency of find because it has to do some unnecessary checking. ? ? 6). Search by file type-type?? ? find. -type D-print #只列出所有的目录?? ??? ? find.-type f-print #只列出所有的文件?? ? find. -type L-print #只列出所有的链接? 7). Search for-mtime (modified time)-atime (time of Change) based on the time of the file (time)-ctime (changing time), the period is +,-to indicate the time before and after?? ? find. -type f-atime-7-print #打印出在最近7天内被访问的所有文件?? ?? ? -amin (Access Time),-mmin (modified time),-cmin (change time

The free command displays the idle, used physical memory and swap memory in the Linux system, and the buffer used by the kernel. In Linux system monitoring tools, the free command is one of the most frequently used commands.1. Command format:free [parameters]2. Command function?:The free command displays system usage and idle memory conditions, including physical memory, interactive area memory (swap), and kernel buffer memory. Shared memory will be ignored3. Command parameters:-B Displays memor

The free command displays the idle, used physical memory and swap memory in the Linux system, and the buffer used by the kernel. In Linux system monitoring tools, the free command is one of the most frequently used commands.1. Command format:free [parameters]2. Command function:The free command displays system usage and idle memory conditions, including physical memory, interactive area memory (swap), and kernel buffer memory. Shared memory will be ignored3. Command parameters:-B Displays memory

Swap partition Swap:When the CPU is running out of memory, it temporarily consumes a portion of the hard disk space to store memory information, which is the swap partition.To create a new swap partition swap:1 Create a new partition by setting the ID to create a swap partition2 format swap partition MKSWAP device name3 Start Swap:swapon device name4 View Swap:free Commandsmkswap command : Set up a swap partition swap format via device or fileMkswap [Options] device [size]Parameters:-C: Detect b

. The following suffixes can be used: b for 512-byte blocks (here is the ' default if no suffix is used) C for bytes W for two-byte words K for kilobytes (Units of 1024 bytes) M for megabytes (units of 1048576 bytes) G for gigabytes (units of 1073741824 bytes) Note: The default unit is B, and it represents 512 bytes, so 2 means that 1k,1m is 2048, if you do not want to convert, you can use other unit

-name "*.txt" #在家目录里搜索txt后缀的文件Find/home-iname "*.txt" #忽略大小写(3) Search by file type:Find directory-type type parameter f normal file L symbol connection D directory C character device B block device s socket p FIFO(4) Search by directory depth:Find. -maxdepth 3-type F # Find from current directory, max depth is 3Find. -mindepth 2-type F # Minimum depth of 2(5) Search according to the file's permission or size name type:Find directory-type f-size (+|-) file size # + = Greater than-Indicates less

Base the size of each file on the size of Rfile -S size --size=size adjusts the size of the file ' KB ' according to the options below > 1000 (kilobytes) ' K ' => 1024 (kibibytes) ' MB ' => 1000*1000 (megabytes) ' M ' => 1024*1024 (mebi Bytes) ' GB ' => 1000*1000*1000 (gigabytes) ' G ' => 1024*1024*1024 (gibibytes) or a unit such as T P E Z is based on the following The symbol of the face, depending

Preparing the Linux virtual system installation source #可以使用HTTP, FTP, or NFS are provided to Xen virtual machines for system installation. FTP is used here for installation, very simple and fast. 1) Installation of VSFTPD service # yum Install-y vsftpd # service VSFTPD Start 2 Mount CD to FTP anonymous directory # mount/dev/cdrom/var/ftp/pub/ Description: VSFTPD will support anonymous access after installation. 2. Create a virtual machine 1) Start Installation # virt-install–prompt

. Our fiber is being upgraded, the transmission bandwidth is generally up to MPs (megabytes per second), and the future can even reach GPs (gigabytes per second). These three technological changes are the basic conditions for the future of computer artificial intelligence. Second, the advent of the Big Data era allows computer AI in the next 50 years, there is a breakthrough in weak Ai to strong AI bottlene

automatically creates a locally managed tablespace with automatic segment space management.Can, but need not, specifyEXTENTMANAGEMENTLOCALandSEGMENTSPACEMANAGEMENTAUTOIn this statement. However, the database returns an error if you specifyEXTENTMANAGEMENTDICTIONARYOrSEGMENTSPACEMANAGEMENTMANUAL. The remaining syntax of the statement are the same as for theCREATE TABLESPACEStatement, but can only specify one data file. For example:CREATE bigfile tablespace bigtbs datafile '/u02/oracle/data/b

the space occupied by flat files that store equivalent data. Configure editing Options: --prefix=prefix Specify the installation directory, default to/usr/local/pgsql --bindir= executable directory, default/prefix/bin --sysconfdir= configuration file directory, default/prefix/etc --libdir= library file directory, default/prefix/lib --includedir= header file directory, default/prefix/include --datarootdir=datarootdir set read-only shared files

startup and after startup.Set scope: Global and Reply level, the global level requires Super permissions, and session level only affects the session itself.Setup method: Can be modified by configuration file and startup option before starting, set by the SET clause after startup.Effective period: Global variables are globally visible, but only affect the client that initializes the corresponding session variable from the global variable after the change. The current session and the logged-on se

scope is global and can be used for options files, which belong to dynamic variables.innodb_additional_mem_pool_size={2097152.4294967295} sets the InnoDB storage engine in order to store the intrinsic pool size of the data dictionary and other internal data structures, in bytes. The greater the number of tables, the greater the value of this parameter should be set, and when InnoDB runs out of space for this memory pool, it will request memory space from the operating system and will record war