6.2.1设置局部用户自定义变量$echo $my_variable $my_variable=Hello$echo $my_variableHello主要赋值的等号两边不能有空格,如果出现空格,bashshell会把空格后的值当成一个单独的命令。如果要给变量赋值一个有空格的字符串,则必须用单引号来界定字符串的首和尾。 命名规则:因为系统变量都是大写字母,所以
array()created an empty array calledarray. IFS=Internal Field Separatoris used to specify a delimiter (which is whitespace in my case). array+=("$line")the line variable stores the value of each line in the file and using this argument, it gets stored in an array. ...
tcxt = shell_variables; temp_array = make_var_export_array (tcxt); if (temp_array) add_temp_array_to_env (temp_array, 0, 0);将temp_array添加到export_env中。 最后在execute_disk_command函数中使用了这个变量 exit (shell_execve (command, args,export_env));...
Creating a new variable with the same name overwrites the existing one. Delete Associative Array To delete an associative array, use theunsetcommand and provide the array name: unset example_arrayCopy The command removes the array variable and all the elements. Conclusion After reading this guide,...
When no array variable name is provided to the mapfile command, the input will be stored into the $MAPFILE variable. Note that the mapfile command will split by default on newlines character but will preserve it in the array values, you can remove the trailing delimiter using the -t ...
-a array 将单词清单放入 array 数组中 first last 读取输入到第一个空格或回车,将输入的第一个单词放入 first 中,而其他的则放在 last 中 -p prompt 打印提示,等待输入,并将输入存入 REPLY 中 -r line 允许输入中包含反斜杠 ”\ ” -t timaout:指定等待接受参数的时间 ...
To handle the debugger mode in our current example, you can add a small block to the my-debug-env startup script which will set the shell options as necessary depending on a custom environment variable DEBUGGER to be set or not.
${variable:pos}: 偏移pos个字符,取余下的子串 name=jerry,name:2结果为rryname:2结果为rry{variable:pos:num}: 偏移pos个字符,取num个字符长度的子串 name=‘hello world’, ${name:2:5}结果为“llo w” 字符串处理,将来在bash中经常用的
This section briefly describes the builtins which Bash inherits from the Bourne Shell, as well as the builtin commands which are unique to or have been extended in Bash. 这部分简短地描述了继承自bourne shell的bash的内置命令,还有一些独特的或已被bash扩展的内置命令。
Used to bind a keyboard sequence. break Used to exit from a running loop in script. cd Change the directory to another directory. command Run a specific command without the normal shell lookup. continue Resumes the next iteration of the loop in script. declare Used to declare a variable. di...