Hi,
It seems some things are missing in the bash manual.
Notably definition of command and placements of coproc- and function-definition.
The section 'SHELL GRAMMAR' describes:
- simple-command
- pipeline
- list
- compound-command
- coproc
- function-definition
Simplified, a pipeline is:
[ ! ] command1 [ | command2 ]
A list is a sequence of pipelines separated by ;, &, &&, or ||
and optionally terminated by ;, & or NL.
Within the list description, the and-list and or-list are described as:
and-list: command1 && command2
or-list: command1 || command2
Though the text says that and/or-lists are sequences of pipelines
(separated by && or ||).
That is slightly inconsistent.
A pipeline can be reduced to a command.
I don't think a command can be a pipeline nor a list.
In that case, the and/or list should read:
and-list: pipeline1 && pipeline2
or-list: pipeline1 || pipeline2
These are valid:
: | { :; }
list: pipeline: command1 s|' command2
command1: simple-command
command2: compound-command
{ :; } || :
list: or-list: pipeline1 || pipeline2
pipeline1: command : compound-command
pipeline2: command: simple-command
:() if [ x = x ]; then echo; fi </dev/null && echo
## not useful as the function definition will not be available
## it is here to show a relatively unkown part of the grammar
list: and-list: pipeline1 && pipeline2
pipeline1: command: function-definition
pipeline2: command: simple-command
This is not valid:
: & && :
list: and-list != list && simple-command
It seems command can be:
- simple-command
- compound-command
- function-definition
- coproc
A command can not be a list nor a pipeline.
[ Start of the grammar would be a list. ]
But maybe a command can be a pipeline, otherwise this is not parsable:
! ! :
list: pipeline: ! command
command: pipeline: ! simple-command
Or the, simplified, pipeline definition should be:
pipeline: [ ! ]* command1 [ | command2 ]*
Any thoughts?
Regards, Mike Jonkmans
(sidenote: 'time time ls' is only printing time once - nice)
