On 7/29/20 1:35 AM, Dale R. Worley wrote: > Ralph Beckmann <r...@rbx.de> writes: >> I found this misbehaviour in Bash 5 (e.g. GNU bash, version >> 5.0.16(1)-release (x86_64-pc-linux-gnu)): >> >> $ BLA="1\.2"; echo 'x/'$BLA'/y/' >> \x/1\.2/\y/ >> >> I don't see any reasonable reason for the generated backslashes here. > > My guess is that you're running into the fact that there are two types > of quoting character. One quotes *any* character that follows it, and > thus it never appears in "the output" unless it was doubled in the > input. The other type *only* quotes characters that are somewhow > special in that particular context. Reading the manual page: > > Enclosing characters in double quotes preserves the literal value of > all characters within the quotes, with the exception of $, `, \, and, > when history expansion is enabled, !. The characters $ and ` retain > their special meaning within double quotes. The backslash retains its > special meaning only when followed by one of the following characters: > $, `, ", \, or <newline>. > > So backslash-inside-double-quotes-in-bash is of the second type, it only > quotes things that would otherwise be special. So the value of $BLA is > 1-\-.-2, whereas if the period was replaced by $, $BLA would only have 3 > characters: > > $ BLA="1\$2"; echo 'x/'$BLA'/y/' > x/1$2/y/ >
I'm not sure what point you're trying to make here. Are you arguing that *printing* these backslash escapes is valid behavior here, and the reporter has merely misunderstood the shell rules? -- Eli Schwartz Arch Linux Bug Wrangler and Trusted User
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