string 用另一个字符替换字符串中的某些字符
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Replacing some characters in a string with another character
提问by Amarsh
I have a string like AxxBCyyyDEFzzLMNand I want to replace all the occurrences of x, y, and zwith _.
我有一个像AxxBCyyyDEFzzLMN这样的字符串，我想用_替换所有出现的x、y和z。
How can I achieve this?
我怎样才能做到这一点？
I know that echo "$string" | tr 'x' '_' | tr 'y' '_'would work, but I want to do that in one go, without using pipes.
我知道这echo "$string" | tr 'x' '_' | tr 'y' '_'行得通，但我想一次性完成，而不使用管道。
回答by jkasnicki
echo "$string" | tr xyz _
would replace each occurrence of x, y, or zwith _, giving A__BC___DEF__LMNin your example.
将取代的每次出现x，y或z有_，给A__BC___DEF__LMN你的例子。
echo "$string" | sed -r 's/[xyz]+/_/g'
would replace repeating occurrences of x, y, or zwith a single _, giving A_BC_DEF_LMNin your example.
将替换重复出现的x,y或z用单个_，A_BC_DEF_LMN在您的示例中给出。
回答by Matthew Flaschen
回答by Dylan Daniels
You might find this link helpful:
您可能会发现此链接很有帮助：
http://tldp.org/LDP/abs/html/string-manipulation.html
http://tldp.org/LDP/abs/html/string-manipulation.html
In general,
一般来说，
To replace the first match of $substring with $replacement:
用 $replacement 替换 $substring 的第一个匹配项：
${string/substring/replacement}
To replace all matches of $substring with $replacement:
用 $replacement 替换 $substring 的所有匹配项：
${string//substring/replacement}
EDIT: Note that this applies to a variable named $string.
编辑：请注意，这适用于名为 $string 的变量。
回答by Michael
read filename ;
sed -i 's/letter/newletter/g' "$filename" #letter
^use as many of these as you need, and you can make your own BASIC encryption
^根据需要使用尽可能多的这些，并且您可以制作自己的 BASIC 加密
回答by Benjamin W.
Here is a solution with shell parameter expansion that replaces multiple contiguous occurrences with a single _:
这是一个带有 shell 参数扩展的解决方案，它用单个 替换多个连续的事件_：
$ var=AxxBCyyyDEFzzLMN
$ echo "${var//+([xyz])/_}"
A_BC_DEF_LMN
Notice that the +(pattern)pattern requires extended pattern matching, turned on with
请注意，该模式需要扩展模式匹配，打开时使用+(pattern)
shopt -s extglob
Alternatively, with the -s("squeeze") option of tr:
或者，使用-s（“挤压”）选项tr：
$ tr -s xyz _ <<< "$var"
A_BC_DEF_LMN
