help read 1read: read [-ers] [-a array] [-d delim] [-i text] [-n nchars] [-N nchars] [-p prompt] [-t timeout] [-u fd] [name ...]2Read a line from the standard input andsplitit into fields.34Reads a single line from the standard input, or fromfiledescriptor FD5ifthe...
o /var The variable subdirectory, where programs record runtime information. System logging, user tracking, caches, and other files that system programs create and manage are here. (You’ll notice a /var/tmp directory here, but the system doesn’t wipe it on boot. o /bin:包含可直接运行的...
readarray: readarray [-n count] [-O origin] [-s count] [-t] [-u fd] [-C callback] [-c quantum] [array] Read lines from a file into an array variable. A synonym for `mapfile'. readonly: readonly [-aAf] [name[=value] ...] or readonly -p Mark shell variables as unchan...
tac FILENAME[ ...]|STDIN tail 显示后几行。 tail [-f -n COUNT] FILENAME[ ...]|STDIN -f:持续检测文件。 -n:显示后COUNT行。若COUNT以+开头,则从第COUNT(含)行开始。 文本处理 awk 以行为单位操作文本列。 awk [-F 'REGEXP' -v VAR=VALUE] '[CONDITION] {ACTION} [[CONDITION] {ACTION} ...
To channel a file to a program’s standard input, use the < operator: 要将文件传递给程序的标准输入,请使用 < 运算符: 代码语言:sh AI代码解释 $head</proc/cpuinfo You will occasionally run into a program that requires this type of redirection, but because mostUnixcommands accept filenames as...
我们 可以使用命令 help readarray 来查看 readarray 命令的帮助信息。 purleEndurer @ bash ~ $ help readarray readarray: readarray [-n count] [-O origin] [-s count] [-t] [-u fd] [-C callback] [-c quantum] [array] Read lines from a file into an array variable. ...
| Variable_name | Value | +---+---+ | query_cache_limit | 2097152 | | query_cache_min_res_unit | 4096 | | query_cache_size | 203423744 | | query_cache_type | ON | | query_cache_wlock_invalidate | OFF | +---+---+ 各字段的解释: query_cache_limit:超过此...
(For example, the bash shell reads the PS1 variable before displaying the prompt.) Shell可以存储临时变量,称为Shell变量,其中包含文本字符串的值。 Shell变量在脚本中跟踪值非常有用,而且一些Shell变量可以控制Shell的行为方式(例如,bash Shell在显示提示符之前会读取PS1变量)。
while read pkg version; do echo "Package: $pkg Version: $version"; done < packages.txtCopy In this example, we performed word splitting on each line. We put the first word of a line into the pkg variable and its corresponding version into the version variable. At the end of the loop...
This variable is equivalent to the ONIE installer command line option --ztp Edit the Image File Because the Cumulus Linux image file is a binary file, you cannot use standard text editors to edit the file directly. Instead, you must split the file into two parts, edit the first part, ...