Re: string escaping in bash

[Alex fxmbsw7 Ratchev]

i figured as much :

str=a\\ttab\ and\ a\ newline\\nand\ \\backslashes\\$'\n'
str=${str//\\\\/$'\1'} str=${str//\\n/$'\n'} str=${str//\\t/$'\t'}
str=${str//$'\1'/\\} ; printf %s "$str"
a tab and a newline
and \backslashes\

On Fri, Mar 12, 2021 at 5:40 PM Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com>
wrote:

> i see
> well manual chaining then
>
> var=b\\c\\tab\\t\\bnewline\\n\\\\n var=${var//\\n/$'\n'}
> var=${var//\\t/$'\t'} vvar=${var//\\/\\\\} ; printf %s "$var"
>
> but that doesnt cover \\ backslashes yet, eg \\n for \n liteeral
> no idea of your needs, maybe you can describe in more detail
>
> On Fri, Mar 12, 2021, 17:07 Peng Yu <pengyu.ut@gmail.com> wrote:
>
>> No. `printf %b '\a'` prints a bell character. But I still want a slash
>> and the character "a". Basically, I only want to treat \\ \n and \t
>> specially. All others should be treated literally.
>>
>> On 3/12/21, Alex fxmbsw7 Ratchev <fxmbsw7@gmail.com> wrote:
>> > you may be looking for
>> > # printf %b "$str"
>> > to interpret the string by prrintf
>> >
>> > or mass chained singular statements, like you showed or similiar
>> >
>> > On Fri, Mar 12, 2021, 16:05 Peng Yu <pengyu.ut@gmail.com> wrote:
>> >
>> >> Hi,
>> >>
>> >> I wondering if there is a simple but robust way to implement string
>> >> escaping.
>> >>
>> >> Specifically, the string "\n" (a slash and the letter "n") should be
>> >> replaced as a newline character, the string "\t" (a slash and the
>> >> letter "t") should be replaced as a tab character, and "\\" (two
>> >> consecutive slashes should be replaced with a single slash. All other
>> >> characters and their preceding slash (if there is) should remain as
>> >> is.
>> >>
>> >> If I use a multi-string-replacement strategy, it will not be robust.
>> >> For example, if I do it in the order 1) \\ -> \, 2) \n -> newline, \\n
>> >> will not be replaced correctly. The result should be "\n" (a slash
>> >> followed by the letter "n").
>> >>
>> >> $ x='\\n'; x=${x//\\\\/\\}; x=${x//\\n/$'\n'}; declare -p x
>> >> declare -- x="
>> >> "
>> >>
>> >> Does anybody have a robust way to implement this in bash?
>> >>
>> >> --
>> >> Regards,
>> >> Peng
>> >>
>> >>
>> >
>>
>>
>> --
>> Regards,
>> Peng
>>
>