Checking for substring in bash using if else statement If you are familiar with theconditional statements in bash, you can use it to check if a string contains the substring in the following manner: if [[ $fullstring == *"$substr"* ]]; Simple example for checking substring The double br...
valint() #@ USAGE: valint INTEGER case ${1#-} in ## Leading hyphen removed to accept negative numbers *[!0-9]*) false;; ## the string contains a non-digit character *) true ;; ## the whole number, and nothing but the number esac 如果函数体用括号括起来,那么它是在子 shell ...
Using the “If -Z” Statement Sometimes, it is required to check if a string variable is empty or if it contains a string of zero length. There are many options in Bash to do this task. Using the “-z” option with the “if” statement is one of the ways to check whether a vari...
I have had so many instances where I wanted to check if a value was present in an array or not. You can probably iterate over all the array items and check it individually, but what if I give you the red pill? I have created an array in which there is a stringasdfand I want to...
Trim all white-space from string and truncate spacesThis is an alternative to sed, awk, perl and other tools. The function below works by abusing word splitting to create a new string without leading/trailing white-space and with truncated spaces....
Create a Bash file with the following script that takes a string value and search the range of characters from “a” to “e” in the string. #!/bin/bash #Take the main string read -p "Enter the main string value: " strValue #Check if the string contains any character from a to ...
if ! grep -q lookupWord "$myFile"; then echo 'Failed to grep'; fi How to use the BASH_REMATCH variable with the Regular Expression Operator =~? The Regular Expression conditional operator =~ takes a string value on the left side and a Bash extended regular expression on the right si...
如果if结构使用的不是test命令,而是普通命令,比如上一节的((...))算术运算,或者test命令与普通命令混用,那么可以使用 Bash 的命令控制操作符&&(AND)和||(OR),进行多个命令的逻辑运算。$ command1 && command2 $ command1 || command2对于&&操作符,先执行command1,只有command1执行成功后, 才会执行command2。
contains the portion of the string matching the entire regular expression. Substrings matched by parenthesized subexpressions within the regular expression are saved in the remaining BASH_REMATCH indices. The element of BASH_REMATCH with index n is the portion of the string matching the nth ...
/bin/bash # declare STRING variable STRING="Hello World" #print variable on a screen echo $STRING Navigate to a directory where your hello_world.sh is located and make the file executable: $ chmod +x hello_world.sh Now you are ready to execute your first bash script:...