bash shell参数展开(Shell Parameter Expansion):替换变量(variable)中的字符串 在写bash shell脚本时,如果遇到要替换变量中的字符串,首先想到的就是用sed命令,比如下面的示例将变量str中的数字123替换成UUU: $ str=hello,word,123 $ echo...$str | sed -E -e 's/[0-9]/U/g' hello,word,UUUU 上面的...
将此文件设为 Haiyong.txt,内容如下: 要替换文件中的文本,我们将使用 open() 函数以只读方式打开文件。...# 创建一个变量并存储我们要搜索的文本 search_text = "资源" # 创建一个变量并存储我们要添加的文本 replace_text = "进群" # 使用 open() 函数以只读模式打开我们的文本文件...语法:路径(...
# stringZ=abcABC123ABCabc # Only replace once # echo ${stringZ/abc/xyz} # xyzABC123ABCabc,从前到后替换一次 # echo ${stringZ/#abc/xyz} # xyzABC123ABCabc,明确从前到后替换一次 # echo ${stringZ/%abc/xyz} # abcABC123ABCxyz,明确从后到前替换一次 # Replace all substring matched # echo $...
{varilable#*pattern}: 查找variable中自左而右第一次被pattern匹配到的串,将此串及向左的所有内容都删除{varilable##*pattern}: 查找variable中自左而右最后一次被pattern匹配到的串,将此串及向左的所有内容都删除 {varilable%pattern*}:查找variable中自右而左第一次被pattern匹配到的串,将此串及向右的所有...
${string/r/_}: The syntax follows this pattern: {variable//pattern/replacement}. In this specific case: //r/_ tells Bash to replace first occurrence of r with _ in the value of string. To deep dive further: / indicates a single replacement (i.e., replace first occurrence, not just...
{string/test/replace}" # output: replace test hello world string="text testhello world" echo "${string/test/replace}" # output: text replacehello world string="test test hello world" echo "${string/test}" # output: test hello world # 通过变量删除 string="test test hello world" ...
${VAR%PATTERN} 删除最后一次匹配的模式及其右边的字符. ${VAR%%PATTERN} 删除第一次匹配的模式及其右边的字符. ${VAR/PATTERN/REPLACE} 替换第一次匹配的字符. ${VAR//PATTERN/REPLACE} 替换所有匹配的字符. ${VAR/PATTERN} 删除第一次匹配的字符. ${VAR//PATTERN} 删除所有匹配的字符.长度...
5. Find and Replace String Values inside Bash Shell Script Replace only first match ${string/pattern/replacement} It matches the pattern in the variable $string, and replace only the first match of the pattern with the replacement. $catfirstmatch.sh#! /bin/bash ...
In this example we declare simple bash variable and print it on the screen ( stdout ) with echo command. #!/bin/bash STRING="HELLO WORLD!!!" echo $STRING 1. 2. 3. Your backup script and variables: #!/bin/bash OF=myhome_directory_$(date +%Y%m%d).tar.gz ...
A variable in bash can contain a number, a character, a string of characters, etc. You have no need to declare a variable, just assigning a value to its reference will create it.Example:str="hello world"The above line creates a variable str and assigns "hello world" to it. The value...