How to check if a string is in an array? How to use the Bash ternary operator? How to negate an if condition in a Bash if statement? (if not command or if not equal) How to use the BASH_REMATCH variable with the
'Else if'in bash scripting, often written as'elif', is used to check multiple conditions in your code. It is used with the syntax,if [firstStatement]; then... elif [secondCondition]; then... else. It’s a powerful tool that allows your scripts to make decisions based on various scen...
To negate the test expression, use the logicalNOT(!) operator. Whencomparing strings, always use single or double quotes to avoid word splitting and globbing issues. Below are some of the most commonly used operators: -nVAR- True if the length ofVARis greater than zero. ...
而if [ ! -z err]||[!−eapk ]; then 没问题; 整数比较 : -eq 等于,如:if [ "a"−eq"b" ] -ne 不等于,如:if [ "a"−ne"b" ] -gt 大于,如:if [ "a"−gt"b" ] -ge 大于等于,如:if [ "a"−ge"b" ] -lt 小于,如:if [ "a"−lt"b" ] -le 小于等于,如:if...
if..then..else..if..then..fi..fi..(Nested Conditionals) 语法: if [[ condition ]] then statement elif [[ condition ]]; then statement else do this by default fi 1. 2. 3. 4. 5. 6. 7. 8. 为了创建有意义的比较,我们也可以使用AND -a和OR -o。
./if-wild.sh Nested If Statements You can put anifstatement inside anotherifstatement. This is perfectly acceptable, but nestingifstatements makes for code that is less easy to read, and more difficult to maintain. If you find yourself nesting more than two or three levels ofifstatements, yo...
The script in a Bashcasestatement has two exit statuses: 0. The return status indicates the input did not match any defined pattern. Executed command status. If a command matches the input variable to a pattern, the exit status of the executed command is returned. ...
Incorrect use of a test operator in a Conditional Statement like using -z instead of -n in a if condition Incorrect use of an Arithmetic operator like multiplying instead of diving a number Incorrect condition to exit from a Bash Loop like when using a while loop instead of an until loop ...
There must be space before and after the conditional operator (=, ==, <= etc). Otherwise, you'll see an error like "unary operator expected". Now, let's create an example scriptroot.sh.This script will echo the statement “you are root” only if you run the script as the root use...
条件语句, if/then/elif 在某些情况下,我们需要做条件判断。比如判断字符串长度是否为0?判断文件foo是否存在?它是一个链接文件还是实际文件?首先,我们需要if命令来执行检查。语法如下: if condition then statement1 statement2 ... fi 当指定条件不满足时,可以通过else来指定其他执行动作。 if condition...