记住:等号的两边不能有空格! Advanced Bash-Scripting Guide: 4.2. Variable Assignment 写道 = the assignment operator (no space before and after) Caution Do not confuse this with = and -eq, which test, rather than assign! Note that = can be either an assignment or a test operator, depending ...
Using the multiple variable assignment technique in Bash scripts can make our code look compact and give us the benefit of better performance, particularly when we want to assign multiple variables by the output of expensive command execution. For example, let’s say we want to assign seven vari...
$ hello_world="value" # Create the variable name. $ var="world" $ ref="hello_$var" # Print the value of the variable name stored in 'hello_$var'. $ printf '%s\n' "${!ref}" value 或者,在bash4.3+上: $ hello_world="value" $ var="world" # Declare a nameref. $ declare -...
${variable/pattern/substi}:替换第一次出现 ${variable//pattern/substi}:替换所有的出现 ${variable/#pattern/substi}:替换行首被pattern匹配到的内容 ${variable/%pattern/substi}: 行尾 pattern可以使用globbing中的元字符: * ? 查找删除: ${variable/pattern} ${variable//pattern} ${variable/#pattern} ...
）# 使用变量：echo $Variableecho "$Variable"echo '$Variable'# 当你赋值 (assign) 、导出 (export)，或者以其他方式使用变量时，变量名前不加 $。# 如果要使用变量的值， 则要加 $。# 注意： ' (单引号) 不会展开变量（即会屏蔽掉变量）。# 在变量内部进行字符串代换echo ${Variable/Some/A}# 会...
When creating scripts, we should take into account that every binary shell file starts with what is commonly known as "she-bang" (also known as sh-bang or hashbang). This is the beginning of the script title, and the first line of code indicates which shell you will use. When making ...
我用它来写电子邮件、新闻组文章、shell 脚本、PostScript 程序、网页等等。 文本编辑器对纯文本文件进行操作。它只存储您键入的字符;它没有添加任何隐藏的格式代码。如果我在文本编辑器中键入A并按回车键,然后保存它,文件将包含两个字符:一个和一个换行符。包含相同文本的文字处理文件要大几千倍。(带字 ,文件...
Variable names with a dollar sign can also be used inside other strings in order to insert the value of the variable into the string: echo"I went to school in$the_empire_state." ## I went to school in New York. When writing a Bash script, the script gives you a few variables for...
Simple Variable Declaration: Write a Bash script that declares a variable named "name" and assign it the value " Marcela". Print the value of the variable to the terminal. Code: #!/bin/bash # Shebang line: Indicates the path to the shell interpreter (in this case, bash) ...
if the variable $F is not ALREADY set to a value, assign "String Value 4" ... F=${F:="String Value 4"} echo "A=$A" echo "B=$B" echo "C=$C" echo "D=$D" echo "E=$E" echo "F=$F" exit 0 $ ./a.sh A=String Value 1 ...