The exit code of the last command you run For every Linux command you run on a shell, it must return an exit status. Usually, the exit status is represented with an integer number, where 0 means that the script/command worked successfully without errors. Any other number besides zero (0)...
Return value is returned by using "return xxx". xxx is in [0,255], saved in $?. Return a string is invalid. If no "return xxx" in function, return the result of last command. Two ways to get the return value: foo i=$? foo() { echo 3 } i=`foo` Use keyword "local" to ...
-- return value of the last synchronous command. */ case '?': temp = itos(last_command_exit_value); break; 三、bash对于set选项处理位置 对应的,在内核构建的时候,可以看到每次执行命令前都会执行 set -e ,bash手册对于该命令的说明为: -e Exit immediately if a simple command (see Section 3.2....
${variable#pattern} # if the pattern matches the beginning of the variable's value, delete the shortest part that matches and return the rest ${variable##pattern} # if the pattern matches the beginning of the variable's value, delete the longest part that matches and return the rest ${va...
Syntax: return [n] where n is a number. If n is not supplied, then it will return the exit code of the last command run. Though, the possible value range for the return builtin is limited to the least significant 8 bits which are 0 to 255. Any number above 255 will just return ...
Captures the exit status code of the previously executed command. $? is a special variable that holds the exit status of the last executed command. Stores the exit status in the variable 'exit_status'. Print the exit status code: echo "Exit status code: $exit_status" Prints the exit stat...
/* WHILE command. */typedef struct while_com{int flags;/* See description of CMD flags. */COMMAND*test;/* Thing to test. */COMMAND*action;/* Thing to do while test is non-zero. */}WHILE_COM; 等等。 主要流程 以下所涉及文件如无特殊说明均处于bash源码的根目录下。 对于一行bash命令的执...
There is three loop constructs available in bash: for-loop, while-loop, and until-loop. All the bash loop constructs have a return status equals to the exit status of the last command executed in the loop, or zero if no command was executed. The For loop...
Let’s break down what’s going on in the Bash script you just created. Bash executes programs in order from the first line in your file to the last line. Theexprcommand can be used toevaluateBashexpressions. An expression is just a valid string of Bash code that, when run, produces ...
if (read_command () == 0) { ... } else if (current_command = global_command) { ... execute_command (current_command); } ... return (last_command_exit_value); } reader_loop()函数中调用read_command()取得命令结构体global_command,然后赋值给current_command并交给execute_command ()去执行...