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_dir
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 || make_home_directory 表示只有当 create_user 返...
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...
The tester who is going to run this script will generally appreciate it if the script terminates shortly after being invoked in case a variable is not correct. No one likes to wait a long time in the execution of the script to find out that a variable was not properly set. # --- # ...
💡 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. ...
1. Using your favorite text editor, create a shell script calledsyntax. If you're using Vim, run the following line in the terminal: vim syntax.shCopy 2. Add the code below to the shell script: # syntax.sh # Declaring functions using the reserved word function ...
# 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:
Used to create an array of strings. ${array[0]} Used to get the first element of the array. ${array[*]} Used to get all values in the array. ${array[1]} Get the last value in the array. ${array[@]} Expand all of the array elements. shift Move argument from $2 to $1. ...
# 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"
You can leverage it to create an environment for debugging purposes and define specific shell options or debugging traps. The $ENV variable is similar to the $BASH_ENV. It is used when the shell runs in POSIX compatibility mode.### Define Debug environment ### Filename: my-debug-env trap...