If you want to get the bash result of a last command, you have to introduce the $? variable after the “echo” command. Alternatively, you can use the printf command: Example: If the code doesn’t run properly, the exit code will be 1 or any other number between 1 – 254. Using ...
Exit status 127 tells you that one of two things has happened: Either the command doesn't exist, or the command isn't in your path ($PATH). This code also appears if you attempt to execute a command that is in your current working directory. For example, the script above that you ga...
(If n is omitted, the exit status is that of the last command executed. ) 格式:$? 上一个命令的退出码。 格式:trap "commands" EXIT 退出时执行commands指定的命令。( A trap on EXIT is executed before the shell terminates.) 退出码(exit status,或exit code)的约定: 0表示成功(Zero - Success...
Execute the command: $command_to_execute Executes the command stored in the variable 'command_to_execute'. In this case, it runs the "ls /new_dir" command, listing the contents of the directory /new_dir. Get the exit status code: exit_status=$? Captures the exit status code of the p...
To display the exit code for the last command you ran on the command line, use the following command: $echo$? The displayed response contains no pomp or circumstance. It's simply a number. You might also receive a shell error message from Bash further describing the error, but the exit ...
If no "return xxx" in function, return the result of last command. Two ways to get the return value: foo i=$? foo() { echo 3 } i=`foo` Use keyword "local" to define a local variable in function. Otherwise, the varibale in function is global. Use keyword "exit" in function wi...
You can use the return builtin command to return an arbitrary number instead. Syntax: return [n] where n is a number. If n is not supplied, then it will return the exit code of the last command run. Though, the possible value range for the return builtin is limited to the least ...
/* WHILE command. */typedef struct while_com{int flags;/* See description of CMD flags. */COMMAND*test;/* Thing to test. */COMMAND*action;/* Thing to do while test is non-zero. */}WHILE_COM; 等等。 主要流程 以下所涉及文件如无特殊说明均处于bash源码的根目录下。 对于一行bash命令的执...
Code: #!/bin/bashecho"Hello, world!" Copy Output: ad@DESKTOP-3KE0KU4:~$ ./test1.sh Hello, world! Explanation: In the exercise above, echo "Hello, world!": This command prints the string "Hello, world!" to the standard output. The "echo" command is used to output text to the ...
$? # Exit status of last task $! # PID of last background task $$ # PID of shell $0 # Filename of the shell script $_ # Last argument of the previous command 检查命令返回值 if ping -c 1 google.com; then echo "It appears you have a working internet connection" fi 检查grep 的...