An expression can be: String comparison, Numeric comparison, File operators and Logical operators and it is represented by [expression]: Number Comparisons: -eq - is equal to - if [ "$a" -eq "$b" ] -ne - is not
Now that you are aware of the various comparison expressions let's see them in action in various examples. Use if statement in bash Let's create a script that tells you if a given number is even or not. Here's my script namedeven.sh: #!/bin/bash read -p "Enter the number: " nu...
compound 和 comparison -a 逻辑与 exp1 -a exp2 如果表达式 exp1 和 exp2 都为真的话,那么结果为真。 -o 逻辑或 exp1 -o exp2 如果表达式 exp1 和 exp2 中至少有一个为真的话,那么结果为真。 注意:这与Bash中的比较操作符 && 和 || 非常相像,但是这个两个操作符是用在双中括号结构中的。 [[...
if [ $num -lt 1 ]; then It is the arithmetic or number-based conditions, and this statement allows comparison of integer numbers. This condition is counted as true only if the entered number is less than 1. if [[ “$stringvar” == *string* ]]; then It is the double-bracket sy...
comparison operators as well.# The behavior of test depends on the number of arguments. Read the# bash manual page for the complete specification.# File operators:# -a FILE True if file exists.# -b FILE True if file is block special.# -c FILE True if file is character special.# -d...
The-leoperator in Bash is used to check if the first number is “less than or equal to” the second number. It compares two numbers and returns true if the first number is less than or equal to the second. This operator is part of thecomparison operatorsprovided by Bash for performing ...
Another common error is using the wrong operator in the condition. For example, using ‘=’ instead of ‘-eq’ for numerical comparison can lead to unexpected results. a=5b=5# Incorrect syntaxif[$a=$b];thenecho'a is equal to b'fi# Output:# a is equal to b ...
The -ge operator in Bash is used to check if the first number is “greater than or equal to” the second number. This operator is part of the comparison operators provided by Bash for performing numeric comparisons. Syntax of -ge Operator The syntax of -ge operator with the two operands ...
if [[ “$a” > “$b” ]] if [ “$a” \> “$b” ] 注意“>” 使用在[ ]结构中的时候需要被转义。 -z 字符串为 “null” , 意思就是字符串长度为零 -n 字符串不为 “null” 。 compound comparison -a 逻辑与 exp1 -a exp2如果表达式 exp1 和 exp2 都为真的话, 那么结果为真。
小于,大于号(ASCII Comparison)。 ASCII比较,进行的是变量的ASCII比较,字串?数字?呃...这个...不就是ASCII比较么? 38. <...> 用于标记单词的分界 词界符(word boundary)。 这个是用在正则表达式中的一个特殊分隔符,用来标记单词的分界。 比如: