《How to convert a string to lower case in Bash?》 就是${parameter,,pattern}, 代码语言:javascript 代码运行次数:0 #! /bin/bash# 注意:脚本第一行一定要注明脚本解释器是bash.不能是sh,或dash # 因为sh软连接有可能指向的是dashvar="Hello,Word"# 把变量中的第一个
google上找到这个stackoverflow上的帖子,才知道Bash 4.0以上版本有更好的办法: 《How to convert a string to lower case in Bash?》 就是${parameter,,pattern},${parameter^^pattern}表达式,表达不会改变原来变量的值 #! /bin/bash # 注意:脚本第一行一定要注明脚本解释器是bash.不能是sh,或dash # 因为sh...
new_string=$(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 "$clean_string" | rev): Reverses the new string using the "rev" com...
The ^ operator converts lowercase letters matching pattern to uppercase; the , operator converts matching uppercase letters to lowercase. The ^^ and ,, expansions convert each matched character in the expanded value; the ^ and , expansions match and convert only the first character in the expa...
Change a string to lowercaseCAVEAT: Requires bash 4+Example Function:lower() { # Usage: lower "string" printf '%s\n' "${1,,}" }Example Usage:$ lower "HELLO" hello $ lower "HeLlO" hello $ lower "hello" helloChange a string to uppercaseCAVEAT: Requires bash 4+...
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...
There is no in array operator in bash to check if an array contains a value. Instead, to check if a bash array contains a value you will need to test the values in the array by using a bash conditional expression with the binary operator =~. The string to the right of the operator...
Bash can be configured to be POSIX- conformant by default. OPTIONS In addition to the single-character shell options documented in the description of the set builtin command, bash inter- prets the following options when it is invoked: -c string If the -c option is present, then commands ...
${PARAMETER/PATTERN/STRING} shell 像文件名扩展中那样扩展 PATTERN,并替换 PARAMETER 扩展后的值中最长的匹配模式(若存在匹配模式的话)。为了在 PARAMETER 扩展后的值开头匹配模式,可以给 PATTERN 附上前缀 #,如果要在值末尾匹配模式,则附上前缀 %。如果 STRING 为空,则末尾的 / 可能被忽略,匹配将被删除。使用...
In Linux and Unix systems, tr is a command-line utility that translates, deletes, and squeezes characters from standard input and writes the results to standard output. The tr command can remove repeated characters, convert uppercase to lowercase, and perform basic character replacing and removin...