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Comment by cube2222 | Hacker News Reader

Just to illustrate for others, in fish that would be

  for i in (seq 10); echo $i; end

or usually written as

  for i in (seq 10)
    echo $i
  end

and that is already based on iteration, so for iterating over files, you'll similarly use

  for f in (ls); echo $f; end

and it works the same for arrays.

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You don't even need the (ls) for file iteration:

  for i in *
    echo $i
  end

Fish also has globstar out of the box, so you can do

  for i in **/*
    echo $i
  end

[You don't even need the (ls) for file iteration:

  for i in *
    echo $i
  end

]

You don't even need the for for that (specific example):

echo *

at least in sh and bash.

echo * does not have the newline after each file

True, echo * will print all the filenames on one line, with a space between pairs, but for data processing purposes, the two snippets are equivalent, because as per shell behavior, newline, tab and space are all treated as space, unless quoted. Like the definition of whitespace in the K&R C book. After all, Unix is written in C.

You wouldn’t iterate over `echo *` anyway. This works just fine in bash/sh:

    for file in *; do
        echo "$file"
    done

Also, IIRC, and less commonly seen, you can do:

  for i 
  do 
    # your commands using $i here
  done

which will iterate over all the command line arguments to the script containing that for loop. It is a shortcut for:

  for i in $*
    # note: not for i in *
  # the rest is the same above

This is mentioned in either the shell man page or in the Kernighan & Pike book The Unix Programming Environment.

Your example in fish:

  for i in (seq 10); echo $i; end

directly translated to bash:

  for i in $(seq 10); do echo $i; done

No need for seq :)

    for i in {1..10}; do echo $i ; done

If, for whatever reason, you want leading zeroes - BASH will respect that. Do {01..10}

seq would work in bash too, but it's not part of the language, it's an external tool. C like syntax is more expressive I'd say for simple numerical increments.

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