#!/bin/sh vs #!/bin/bash filename expansion after <

#!/bin/sh vs #!/bin/bash filename expansion after <

[Morten Kjærulff]

Hi,

This script:

#!/bin/sh
echo hello >hello.txt
ls -l
cat hell*
cat < hell*

gives me:

$ ./t.sh
total 2
-rw-r--r-- 1 vp01mkf Domain Users  6 Aug 12 19:51 hello.txt
-rwxr-xr-x 1 vp01mkf Domain Users 60 Aug 12 19:51 t.sh
hello
./t.sh: line 5: hell*: No such file or directory

But if I change line1 to
#!/bin/bash
I get
hello
hello

Is that correct behaviour. I guess so, but why? And what is the rule?

/Morten

Re: #!/bin/sh vs #!/bin/bash filename expansion after <

[Eliot Moss]

On 8/12/2020 1:54 PM, Morten Kjærulff via Cygwin wrote:
> Hi,
> 
> This script:
> 
> #!/bin/sh
> echo hello >hello.txt
> ls -l
> cat hell*
> cat < hell*
> 
> gives me:
> 
> $ ./t.sh
> total 2
> -rw-r--r-- 1 vp01mkf Domain Users  6 Aug 12 19:51 hello.txt
> -rwxr-xr-x 1 vp01mkf Domain Users 60 Aug 12 19:51 t.sh
> hello
> ./t.sh: line 5: hell*: No such file or directory
> 
> But if I change line1 to
> #!/bin/bash
> I get
> hello
> hello
> 
> Is that correct behaviour. I guess so, but why? And what is the rule?

The bash man page describes how its behavior is different when run as sh vs bash :-) ... EM

Re: #!/bin/sh vs #!/bin/bash filename expansion after <

[Andrey Repin]

Greetings, Morten Kjærulff!

> This script:

> #!/bin/sh
> echo hello >hello.txt
> ls -l
> cat hell*
> cat < hell*

> gives me:

> $ ./t.sh
> total 2
> -rw-r--r-- 1 vp01mkf Domain Users  6 Aug 12 19:51 hello.txt
> -rwxr-xr-x 1 vp01mkf Domain Users 60 Aug 12 19:51 t.sh
> hello
> ./t.sh: line 5: hell*: No such file or directory

> But if I change line1 to
> #!/bin/bash
> I get
> hello
> hello

> Is that correct behaviour. I guess so, but why? And what is the rule?

d2u t.sh
???


-- 
With best regards,
Andrey Repin
Wednesday, August 12, 2020 23:07:08

Sorry for my terrible english...

Re: #!/bin/sh vs #!/bin/bash filename expansion after <

[Eliot Moss]

On 8/12/2020 4:07 PM, Andrey Repin wrote:
> Greetings, Morten Kjærulff!
> 
>> This script:
> 
>> #!/bin/sh
>> echo hello >hello.txt
>> ls -l
>> cat hell*
>> cat < hell*
> 
>> gives me:
> 
>> $ ./t.sh
>> total 2
>> -rw-r--r-- 1 vp01mkf Domain Users  6 Aug 12 19:51 hello.txt
>> -rwxr-xr-x 1 vp01mkf Domain Users 60 Aug 12 19:51 t.sh
>> hello
>> ./t.sh: line 5: hell*: No such file or directory
> 
>> But if I change line1 to
>> #!/bin/bash
>> I get
>> hello
>> hello
> 
>> Is that correct behaviour. I guess so, but why? And what is the rule?
> 
> d2u t.sh
> ???

Yes, you need to watch line endings under cygwin!  The usual Windows CR-LF
can cause a world of grief.  You can mount drives to hide this, but doing
so can mess up reading binary files ...

EM

Re: #!/bin/sh vs #!/bin/bash filename expansion after <

[Ken Brown]

On 8/12/2020 1:54 PM, Morten Kjærulff via Cygwin wrote:
> Hi,
> 
> This script:
> 
> #!/bin/sh
> echo hello >hello.txt
> ls -l
> cat hell*
> cat < hell*
> 
> gives me:
> 
> $ ./t.sh
> total 2
> -rw-r--r-- 1 vp01mkf Domain Users  6 Aug 12 19:51 hello.txt
> -rwxr-xr-x 1 vp01mkf Domain Users 60 Aug 12 19:51 t.sh
> hello
> ./t.sh: line 5: hell*: No such file or directory
> 
> But if I change line1 to
> #!/bin/bash
> I get
> hello
> hello
> 
> Is that correct behaviour. I guess so, but why? And what is the rule?

 From https://tiswww.case.edu/php/chet/bash/POSIX:

When invoked as 'sh', Bash enters POSIX mode after reading the startup
files.

The following list is what's changed when 'POSIX mode' is in effect:

   1. Bash ensures that the 'POSIXLY_CORRECT' variable is set.

[...]

   11. Redirection operators do not perform filename expansion on the
      word in the redirection unless the shell is interactive.

[...]


Ken