test.sh > filename:重定向 test.sh 的输出到文件 filename 中。如果 filename 存在的话,那么将会被覆盖。 test.sh &> filename:重定向 test.sh 的 stdout(标准输出)和 stderr(标准错误)到 filename 中。 test.sh >&2:重定向 test.sh 的 stdout 到 stderr 中。 test.sh >> filename:把 test.sh...
This type of for loop is characterized by counting. The range is specified by a beginning (#1) and ending number (#5). The for loop executes a sequence of commands for each member in a list of items. A representative example in BASH is as follows to display welcome message 5 times wit...
Why you can use a bash for loop in one line If you use bash on the command line, this will not guarantee that for loops are inserted into the script. In order to prevent this, it is easiest to use loops directly on the command line and then there will be no problems. How to use...
line done 使用while循环 while read -r line do echo $line done < filename While循环中read命令从标准输入中读取一行,并将内容保存到变量...line中。...在这里,-r选项保证读入的内容是原始的内容,意味着反斜杠转义的行为不会发生。输入重定向...
First, create a file name and execute the following script. Users must note that the ‘*’ is used to read files in the ‘for loop.’ The functioning of the loop is the simple manner by reading each file or folder through the step of the directory and prints with the output in the ...
Let’s create a 3×3 2D array using nested while loop in Bash: #!/bin/bash i=1 while [ $i -le 3 ] do j=1 while [ $j -le 3 ] do echo "Row: $i Column: $j" ((j++)) done ((i++)) done Reading File Line by Line with Bash while Loop ...
while read -r line; do printf '%s\n' "$line" done < "file" 1. 2. 3. 循环遍历文件和目录 不要用ls。 # Greedy example. for file in *; do printf '%s\n' "$file" done # PNG files in dir. for file in ~/Pictures/*.png; do ...
6.循环loop 6.1 while do done, until do done (不定循环) 6.2 for...in...do...done (固定循环) 6.5 for...do...done 的数值处理 7.shell script的追踪与debug 四、补充 1.打印进度条 2.文件描述符(参考第一章18小节) 3.进程检测
While ShellCheck is mostly intended for interactive use, it can easily be added to builds or test suites. It makes canonical use of exit codes, so you can just add ashellcheckcommand as part of the process. For example, in a Makefile: ...
lineCount=$[$lineCount+$lines] fi done echo "The number of text file is $textCount." echo "The number of line of text file is $lineCount." 控制变量 for语句的控制变量,其实就是类似于C风格的for语句。 for((expr1; expr2; expr3));doBODYdone ...