LINENO is set to zero during the execution of aliases or commands in
'eval'. This behaviour is different from that of other shells.
#! /usr/bin/env mksh
alias showlineno='echo $LINENO'
eval 'echo $LINENO'
showlineno
Actual output:
0
0
Expected output:
3 (or 1)
4
This behaviour seems to be inherited from pdksh, but no other shell has it.
Several shells (dash, yash, zsh in native mode, ksh93) start counting
from 1 when executing an 'eval', as if they considered it a separate
script, so they output 1 for the eval. But all shells output 4 for the
alias.
Another test script:
printf "$LINENO "
printf "$LINENO "
eval ' printf "$LINENO "
printf "$LINENO "
printf "$LINENO " '
printf "$LINENO\n"
Output on various shells:
mksh: 1 2 0 0 0 6
lksh: 1 2 0 0 0 6
pdksh: 1 2 0 0 0 6
AT&T ksh88: 1 2 3 3 3 6
AT&T ksh93: 1 2 1 2 3 6
bash: 1 2 5 6 7 6 (?!)
FreeBSD sh: 1 2 1 2 3 6
dash: 1 2 1 2 3 6
yash: 1 2 1 2 3 6
zsh (native): 1 2 1 2 3 6
zsh (sh): 1 2 3 3 3 6 (like ksh88)
(Looks like I may also have to tell bug-bash that the bash behaviour is
weird, and zsh-workers that zsh's sh mode is not emulating any current sh).
HTH,
- M.
