Iterating over inline array in zsh

$for fl in (fileA fileB fileC); echo $fl

Here, ( is parsed as the beginning of a Glob Qualifier, like in ls *(a+2).

The qualifier f stands for files with access rights matching spec, that's why you get the error invalid mode specification, because ileA is not a valid access right spec.

If you try e.g. $for fl in (anotherfileA fileB fileC); echo $fl you get zsh: number expected, because the a qualifier is to select by access time. And so on...

So, how to do it right? -- In zsh there are two possible syntaxes for for loops:^#

• Number one is described in the man page:

  for name ... [ in word ... ] term do list done
  

  So, as @SadBunny already pointed out, the correct syntax of your example is

  for fl in fileA fileB fileC; echo $fl
  

• Number 2 is for the lazy people like me (count the key strokes ;) ), documented in the ALTERNATE FORMS FOR COMPLEX COMMANDS section of man zshmisc:

  for name (word ...) { cmd1; cmd2; }
  

  which can be simplified for only one command in the loop body by omitting the curly brakets:

  for fl (fileA fileB fileC) echo $fl
  

  This form has IMHO two main advantages:

  • easyier to remember (exactly one pair of round brackets, no or one pair of curly brackets)
  • works as for fl (fileA fileB fileC) mycommand $fl as well as for fl ($files) mycommand $fl -- same syntax for literal values or variables.

^# Not counting the arithmetic for loops in the form for (( [expr1] ; [expr2] ; [expr3] )) do list done

Sure it's possible. Remove the brackets:

monsterkill-ub-dt% for fl in (xfile yfile); cat ${fl}
zsh: invalid mode specification

monsterkill-ub-dt% for fl in xfile yfile; cat ${fl}  
x
y

This also works:

monsterkill-ub-dt% for fl in *; cat ${fl} 
x
y