cat

javascript的数组之includes()

由 岁酱吖の 提交于 2019-12-23 04:23:07
includes()方法用来判断一个数组是否包含一个指定的值，根据情况，如果包含则返回true，否则返回false。 1 var array1 = [1, 2, 3]; 2 3 console.log(array1.includes(2)); 4 // expected output: true 5 6 var pets = ['cat', 'dog', 'bat']; 7 8 console.log(pets.includes('cat')); 9 // expected output: true 10 11 console.log(pets.includes('at')); 12 // expected output: false 参数： 第一个：需要查找的元素 第二个：fromIndex，开始查找位置的索引，默认为0 返回值：boolean 来源： https://www.cnblogs.com/huanqiuxuexiji/p/9168069.html

Piping the output to cat

由 ￣綄美尐妖づ 提交于 2019-12-23 02:29:30
问题 I have the following prog written: int main() { printf("one\n"); write(1, "two\n", 4); return 0; } And then i give the command ./a.out | cat at the terminal to which the output comes to be two one instead of one two Why??? 回答1: That's because printf 's output will get buffered by the libc , write 's output will not get buffered. It's a direct , unbuffered operation on a file (stdout) Read this: if stdout is a terminal then buffering is automatically set to line buffered, else it is set to

Linux cat命令

由 时光怂恿深爱的人放手 提交于 2019-12-22 11:21:23
/*--> */ /*--> */ 介绍 cat命令经常会用来查看一个文件的内容，并且结合它本身的一些参数经常可以用来做一些特殊的内容处理。 参数 Usage: cat [OPTION]... [FILE]... Concatenate FILE(s), or standard input, to standard output. -A, --show-all 等同于使用参数-vET -b, --number-nonblank 针对非空行显示行号 -e 等同于使用参数 -vE -E, --show-ends 每行以$结尾 -n, --number 每行都显示行号 -s, --squeeze-blank 将连续的多个空行以显示一个空行 -t 等同于使用参数 -vT -T, --show-tabs 制表符（tab）以^I符合代替 -u (ignored) -v, --show-nonprinting use ^ and M- notation, except for LFD and TAB --help display this help and exit --version output version information and exit With no FILE, or when FILE is -, read standard input. Examples: cat f

Strange grammar in cat command

由 这一生的挚爱 提交于 2019-12-22 10:39:41
问题 First of all, I apologize if this question can be answered with a web search, but I couldn't find anything. There is some grammar in the cat command which I've seen to "repeat" files. cat file{,} Is equivalent to calling cat file file Also, cat file{,}{,}{,}{,} repeats file not four times, but 16 times. In addition, cat file{,,} repeats file 3 times. I would like to know more about this grammar. What is it called? Is it built into cat or is it a shell feature? Are there more features of this

Linux中查看CPU信息

由 让人想犯罪 __ 提交于 2019-12-22 09:20:37
【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> cat /proc/cpuinfo中的信息 processor 逻辑处理器的id。 physical id 物理封装的处理器的id。 core id 每个核心的id。 cpu cores 位于相同物理封装的处理器中的内核数量。 siblings 位于相同物理封装的处理器中的逻辑处理器的数量。 1 查看物理CPU的个数 #cat /proc/cpuinfo |grep "physical id"|sort |uniq|wc –l 2、 查看逻辑CPU的个数 #cat /proc/cpuinfo |grep "processor"|wc –l 3、 查看CPU是几核 #cat /proc/cpuinfo |grep "cores"|uniq 4、 查看CPU的主频 #cat /proc/cpuinfo |grep MHz|uniq 5、 # uname -a 6、 Linux euis1 2.6.9-55.ELsmp #1 SMP Fri Apr 20 17:03:35 EDT 2007 i686 i686 i386 GNU/Linux (查看当前操作系统内核信息) 7、 # cat /etc/issue | grep Linux 8、 Red Hat Enterprise Linux AS release 4

Bash and Script help generating files with variable content

由 别等时光非礼了梦想. 提交于 2019-12-22 01:00:24
问题 Extending this question: How to Create several files from a list in a text file? Summary: cat file_full_of_files_names | tr ' \t' '\n\n' | while read filename; do if test -f "$filename"; then echo "Skipping \"$filename\", it already exists" else cp -i initial_content "$filename" fi done works great for what I want, but I'd like to extend it. The content below is what is found in 'initial_content' <?xml version="1.0" encoding="UTF-8"?> <selector xmlns:android="http://schemas.android.com/apk

Copy and append files to a remote machine: cat error

由 瘦欲@ 提交于 2019-12-22 00:34:15
问题 So, I have a bit of a problem: Originally I was using scp to copy a file from a local machine to a remote machine before I realized that scp overwrites instead of appends. But I need it to append. So I did some Googling and this alternative using cat and ssh popped up instead: cat localfile | ssh user@remoteserver "cat >> remotefile" Problem is, I get this interesting error whenever I use that method: bash: cat: command not found When I normally ssh into my remote machine, I can cat just fine

combining head and tail methods in R

由 流过昼夜 提交于 2019-12-21 18:02:26
问题 I use the head(d) and tail(d) methods in R package utils a lot - frequently one after the other. So i wrote a simple wrapper for the two functions: ht <- function(d, m=5, n=m){ # print the head and tail together cat(" head --> ", head(d,m), "\n", "--------", "\n", "tail --> ", tail(d,n), "\n") } And i got some unexpected results ... can someone please help me understand why? (so i can fix it ... or at least understand your solution!). Some background... Numeric is fine: x <- 1:100 ht(x) As is

create infinite looping repeating file cat in linux/bash

由 夙愿已清 提交于 2019-12-21 16:50:35
问题 What I'd like to do is send a single file "repeatedly" (like cat'ing it an infinite number of times) as input to another program. Is there a way on the command line/using bash? 回答1: Process substitution provides a mechanism by which bash can generate a temporary, readable filename connected to an arbitrary chunk of bash code for you: ./my_program -input <(while cat file_to_repeat; do :; done) This will create a /dev/fd/NN -style name on operating systems that support it, or a named pipe
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