after typing ;ls
I got this return - bash: syntax error near unexpected token `;'
how do I fix this?
2 Answers
The semicolon terminates a command. Usually you don't need it, since a newline will do. But you can use to put multiple commands on one line, e.g.
$ echo -n "hi "; echo there
hi there
or maybe more usefully:
if [ whatever ]; then
Putting a semicolon at the start of a line leaves an "empty" command before it, and apparently the shell syntax forbids it. Yash gives a useful error message:
$ yash -c '; echo hi'
yash -c:1: syntax error: a command is missing before ‘;’
And Ksh and Zsh seem to just ignore the issue:
$ zsh -c '; echo hi'
hi
(But you can't use echo foo;; in those either, since ;; is different from ;, like > is different from >>. ;; is used in case statements.)
The empty command doesn't do anything anyway, so you can just leave the leading semicolon out. Or switch to Zsh, I guess.
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Note that
ksh93 -c 'echo test |; cat'complains butzshdoesn't. In any case, I wouldn't use it anyway as|;may become a new operator in future versions of either shell (like<>;and>;are already special operators in ksh93). Apr 6, 2021 at 13:43 -
@StéphaneChazelas, or
echo test | ; catwith the space. Orfor x in 1 2 3 4; ; do; ; echo $x; done. In Zsh, I mean. I can see some sense in treating a semicolon a bit like a newline in that there can be many, but within a pipeline it seems a bit weird. At least it doesn't allow sprinkling&around in the same way...– ilkkachuApr 6, 2021 at 14:41 -
1See also
array=( ; a ; ; ; b ). It seems;is equivalent to newline in most places which is kind of consistent (though I agree a bit surprising) Apr 6, 2021 at 14:44 -
The
;inecho one; echo twois a control character. The;inif list; then ...is part of theifsyntax. They are different, not equivalent.– user232326Apr 8, 2021 at 5:40 -
@Isaac, not really, see also
if cmd & then...(if cmd |& thenin ksh). The point is that those;,&, newline,|&... still delimit the commands there, and thethenkeyword, like most keywords is only recognised as such in command position (though that's not the whole story asif (true) then echo true; fiworks in most shells (and YMMV for((1))or[[ x ]]in place of(true))) Apr 8, 2021 at 7:17
It is the same syntax error as:
$ ;
bash: syntax error near unexpected token `;'
Which simply means that there should be a cmd before the terminating ;:
$ ls ;
In such cases the ; is a metacharacter that is defined as:
metacharacter
A character that, when unquoted, separates words.
Not equivalent to the ; in the compound command:
if list; then list; else list; fi
As, in this case, it is part of the syntax of the command.
;ls? If so, why? The easy answer is along the lines of "don't do that", but has deeper explanations, depending on your curiosity.:;lsinstead... Or use Ksh or Zsh, which just ignore the empty command. It's somewhat interesting actually that it isn't allowed.