在 Bash 中充分利用这一点可以增加程序的灵活性。例如：create_user && make_home_directory这条语句，只有 create_user 返回 0 时，才会执行 make_home_directory。而create_user; make_home_directory则表示无论 create_user 的返回值是什么，都会执行 make_home_directory。类似的，你也可以通过：create_user |...
A function does not execute when declared. The function's body executes when invoked after declaration. Follow the steps below to create a bash script with various syntax options: 1. Using your favorite text editor, create a shell script calledsyntax. If you're using Vim, run the following ...
tered, an attemptismadetodefine afunctionusing``-f foo=bar'', an attempt is made to assign avaluetoareadonlyvariable, an attemptismadetoassign a valuetoan array variable withoutusingthe compound assignment syntax (see Arrays above), oneofthe namesisnota valid shell variable name, an attempti...
💡 When a shell function is executed, you can access the function name inside the function with the FUNCNAME variable. It is often used when debugging a script in conjunction with the bash environment variables $BASH_LINENO and $BASH_SOURCE. ...
/bin/bash. Next, we create a variable calledTIMESTAMPusing the date command. The%Y%m%d_%H%M%Sformat string specifies the date and time in the format of year, month, day, hour, minute, and second, separated by an underscore: How to Use the Timestamp Variable...
Global variable value after calling function Global content changed Local variable value after calling function In the above output, local variables will have only empty value before and after calling the function. Its scope is only with in the function. It got vanished out of the function, where...
# 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 1. 2. 3. 4. 5. 6. 7. 8. 9. 或者,在bash4.3+上:
In the exercise above, Define a function called "factorial()" using the factorial() { ... } syntax. Inside the function: Declare a local variable 'num' to store the argument passed to the function. Declare another local variable 'result' and initialize it to 1. ...
# Main function if [ $# -eq 0 ]; then _setv_help_ elif [ $# -le 3 ]; then case "${1}" in -n|--new) _setv_create ${2};; -d|--delete) _setv_delete ${2};; -l|--list) _setv_list;; *) if [ -d ${SETV_VIRTUAL_DIR_PATH}${1} ]; ...
The process id of the shell spawned to execute the coprocess is available as the value of the variable NAME_PID. The wait builtin command may be used to wait for the coprocess to terminate. The return status of a coprocess is the exit status of com- mand. Shell Function Definitions A...