Re: [Help-bash] how to understand the xargs

[Greg Wooledge]

On Tue, Dec 27, 2011 at 11:12:31PM +0800, lina wrote:
> #!/bin/sh
> 
> for i in {1..10} ; do

Brace expansion is a bash feature, not a /bin/sh feature.  When you put
#!/bin/sh at the top of your script, you are telling the operating system
to use /bin/sh as the interpreter when you run the script.  And /bin/sh
won't understand brace expansions.

If you wish to use bash features in your scripts, you must use

#!/bin/bash

or

#!/usr/bin/env bash

as your shebang.  This will make the operating system run bash to interpret
your script.

> BTW, on script I used to use for i in $(seq 10)
> just recent trying to learn more, so do some practice.

seq(1) is Linux-only.  Some other OSes have jot(1) instead, but both of
those are nonstandard (and they have incompatible syntax).

The correct way to count to 10 in /bin/sh is:

i=1
while [ $i -le 10 ]; do
  ...
  i=$((i+1))
done