if [[ "$s1" == "$s2" ]] - moinudin 4 我必须使用这个答案来将一个变量与一个固定字符串进行比较。 - Wok 21 双等号在第一个案例中是一个错误。Bash允许它,但是可移植的变体应该是 if [ "$s1" = "$s2" ]。另请参见Rahul的答案。 - tripleee 4 你好,我想知道为什么这里有空格会出问题 -...
After opening the newly created bash file via GNU editor, input the code displayed in the image below. Begin by adding the bash extension, then declare a variable named "val" with a string value of "Aqsa". Inside the "if" statement, set a condition to check if the string value of var...
Use the Linux Bash if statement to build conditional expressions with anifthenfistructure. Addelifkeywords for additional conditional expressions, or theelsekeyword to define a catch-all section of code that's executed if no previous conditional clause was executed. All non-trivial Bash scripts need...
How to do string comparison and check if a string equals to a value? 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...
if [[ ]]; then fi Exp: if[[$USER='username']];thenecho"true"elseecho"false"fi not equal:!= numeric equality:-eq not equals:-ne is empty:-z if[[1-eq1]];if[[-z$USER]]; Elif if[[-z$USER]];thenecho"user is empty"elif[[1-eq1]];thenecho"1==1"elseecho"false"fi ...
Note: If we remove whitespace before and after the=operator in theifstatement, for example,if [ "$S1"="$S2" ], it will not compare the strings accurately. The!=(is not equal) operator is used for the inequality matching of two strings. We can use this operator inifstatement usingif...
if [[ $i -eq 9 ]] then echo "Number $i!" ((i++)) continue fi echo $i ((i++)) done The code increments a variable and loops until the value reaches10. When the variable equals9, the program outputs a different message. Thecontinuestatement restarts theuntilloop and continues as...
例子 ./cidr-to-ip.sh [OPTION(only one)] [STRING/FILENAME] -h 显示此帮助屏幕 -f 在...
if [[ $i == '2' ]] then echo "Number $i!" break fi echo "$i" done echo "Done!" When the integer value equals two ($i == '2'), the program prints a message and exits theforloop thanks to thebreakstatement. As a result, running the script ends the program when the variabl...
The if statement allows you to specify courses of action to be taken in a shell script, depending on the success or failure of some command. It is a conditional statement that allows a test before performing another statement. The syntax for the simplest