new_string=$(echo "$input_string" | tr -dc '[:alnum:]' | tr '[:upper:]' '[:lower:]'): Removes non-alphanumeric characters and converts the string to lowercase using the "tr" command. reversed_string=$(echo "$cl
Use regex on a stringThe result of bash's regex matching can be used to replace sed for a large number of use-cases.CAVEAT: This is one of the few platform dependent bash features. bash will use whatever regex engine is installed on the user's system. Stick to POSIX regex features if...
Change a string to lowercaseCAVEAT: Requires bash 4+Example Function:lower() { # Usage: lower "string" printf '%s\n' "${1,,}" }Example Usage:$ lower "HELLO" hello $ lower "HeLlO" hello $ lower "hello" helloChange a string to uppercaseCAVEAT: Requires bash 4+...
How to shuffle the elements of an Array in a shell script? There are two reasonable options to shuffle the elements of a bash array in a shell script. First, you can either use the external command-line tool shuf that comes with the GNU coreutils, or sort -R in older coreutils versions...
x="a string." echo $x 执行一下看看?又出现了新的关键字:let。关于整数变量计算,有如下几种:" + - * / % ",他们的意思和字面意思相同,在*和/之前必须冠以反斜线,已防被SHELL先行解释。整数运算一般通过 let 和 expr 这两个指令来实现,如对变量 x 加 1 可以写作:let "x = $x + 1" 或者 x...
Bash's exit status is the exit status of the last command executed in the script. If no commands are executed, the exit status is 0. An attempt is first made to open the file in the current directory, and, if no file is found, then the shell searches the directories in PATH for ...
A string of characters used to identify a file. job A set of processes comprising a pipeline, and any processes descended from it, that are all in the same process group. job control A mechanism by which users can selectively stop (suspend) and restart (resume) execution of processes. ...
Trim all white-space from string and truncate spaces Use regex on a string Split a string on a delimiter Change a string to lowercase Change a string to uppercase Trim quotes from a string Strip all instances of pattern from string Strip first occurrence of pattern from string Strip pattern ...
Method 3: Use the awk command to Remove Empty Lines in Bash In this method, we'll make advantage of awk, a built-in keyword in Bash Script. The general-purpose scripting language awk was created for sophisticated text data processing. Text manipulation, reporting, and analysis are its main...
0 Expands to the name of the shell or shell script. This is set at shell initialization. If bash is invoked with a file of commands, $0 is set to the name of that file. If bash is started with the -c option, then $0 is set to the first argument after the string to be executed...