On 3/12/20 4:53 PM, Zack Weinberg wrote: > > On further investigation, there is a concrete reason why autoconf 2.69 > prefers SHELL=/bin/bash to SHELL=/bin/dash, namely that dash doesn't > support $LINENO, necessitating a complicated and fragile workaround The $LINENO support in dash is configurable and enabled by default. You have to disable it with ./configure --disable-lineno. Apparently, Debian does so [0] to ensure that autoconf scripts with bashisms in them keep working. In other words, they break dash just enough that bash will be used as a fallback. [0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=842242