This way, to test if a number, n, is prime for numbers greater than 3, we perform a series of steps: check if n is divisible by 2 or 3 check if n is divisible by numbers of the form 6k-1 or 6k+1 that are less than or equal to the square root of n If n satisfies neither...
在下面的示例中,我们包含了一个 if-else 语句,用于检查并打印出 1 到 7 之间的偶数和奇数。 #!/bin/bash for (( n=1; n<=7; n++ )) do # Check if the number is even or not if (( $n%2==0 )) then echo "$n is even" else echo "$n is odd" fi done 使用“Continue”语句 “...
您可以在 C 风格的 for 循环中包含条件语句。在下面的示例中,我们包含了一个 if-else 语句,用于检查并打印出 1 到 7 之间的偶数和奇数。 #!/bin/bashfor(( n=1; n<=7; n++ ))do# Check if the number is even or notif(($n%2==0))thenecho"$nis even"elseecho"$nis odd"fidone 使用“Co...
If the $count variable is zero, the grep output was empty, passed to the wc-1 because the pattern was not matched. The script then outputs the message No match found. to the console using the echo command. That’s all about Bash check if grep result is empty. Was this post helpful?
您可以在 C 风格的 for 循环中包含条件语句。在下面的示例中,我们包含了一个 if-else 语句,用于检查并打印出 1 到 7 之间的偶数和奇数。 代码语言:javascript 代码运行次数:0 运行 AI代码解释 #!/bin/bashfor((n=1;n<=7;n++))do# Checkifthe number is even or notif(($n%2==0))then ...
1 done } cmd_with_process() { $1 & pid=$! process $pid & wait $pid if [ $? -eq 0 ]; then echogreen "[ok]" else echo_red "[fail]" fi } case $ in check_cmd) shift cmd_with_process"$*" ;; *) echo_blue "Usage $0 [check_services|check_cmd]" echo_yellow "For...
if [ ${#array1[@]} -eq 0 ]; then This time, we got the size of the array and test it with the number zero. Let's see both methods with sample examples. Check empty bash array with string comparison We are going to use two elements to check if bash array is empty or not. On...
在脚本中,if语句的不同部分通常是良好分隔的。以下是一些简单的例子: 7.1.1.3. 检查文件 第一个例子检查一个文件是否存在: anny ~> msgcheck.shanny ~> 7.1.1.4. 检查shell选项 加入到你的Bash配置文件中去: # These lines will print a message if the noclobber option is set: ...
check-scripts:# Fail if any of these files have warningsshellcheck myscripts/*.sh or in a Travis CI.travis.ymlfile: script:# Fail if any of these files have warnings-shellcheckmyscripts/*.sh Services and platforms that have ShellCheck pre-installed and ready to use: ...
It can also be used to check if a command exists. For example, the above code is similar to the previous two but uses the type -p command to check if the grep command exists. Again, we used the > operator to redirect the command’s output to the null device, which discards the ...