My point is that adding scoped lifetime management to file descriptors in a shell wouldn't fall nearly as far outside the current model as you suggest.
Noted. I don't agree.
Quote:
read x < $f #Is that quite simple enough?
We already use $. This'd change the meaning of plenty of existing code where $f would be a file name. Unless you decide to do both, in which case this is a line of code that does two completely different things depending on what type of variable it is. You're not just adding anonymous files to your shell, you're adding operator overloading!
Quote:
Alternately, "read x <&$f" would make it plain that $f is an open file and not a filename.
$ means string, period. Pick something else.
Quote:
some_command $f # It's actually not too hard to make this do what the user intends...
How do you know that's what the user wants? How do you know the command even reads from stdin? How much code would this break in what bizzare ways when someone opens a file by accident? If you want implicit redirections, you redirect a code block to get everything inside it redirected.
This line will also do completely different things under different circumstances -- string or file -- even though it isn't a branch or control statement. New kinds of spaghetti logic can be made out of it. And now you need more shell extensions to tell the difference between file and string to avoid these weird corner cases.
Quote:
First, the shell could handle it like process redirection: assign the file $f some numeric FD in the new process, then in place of the argument $f, substitute /dev/fd/(some number)
If you still think the shell assigns these numbers, I don't know what to tell you.
Yes, that mode of anonymous redirection increases the code block level, that's unavoidable -- how else are you going to define scope but code blocks?
For global, but anonymous filedescriptors, How about this for a syntax:
That even works, if you write an 'open' function, since the second line isn't a new syntax.
Hi ,
I am having one situation in which I need to run some simple unix commands after doing "chroot" command in a shell script. Which in turn creates a new shell.
So scenario is that
- I need to have one shell script which is ran as a part of crontab
- in this shell script I need to do a... (2 Replies)
Hi
I tried with bash --login option. but the output is
siva:~$ bash --login
siva:~$
is there any way to make the shell ask for user id and password ( and login as different user instead of using sudo / su )
Thx in advance
Siva (3 Replies)
i have a small problem getting a batxh shell script to run in shell
this is the code
the problem seems to be centered around the ffmpeg command, something maybe to do with the ' ' wrapping around the vhook part command
this is a strange problem , if i take the ffmpeg command and... (1 Reply)
Hi,
I am using HP-UNIX.
I have a requirement as below
I have to change env twice like:
cadenv <env>
cadenv <env>
ccm start -d /dbpath
ccm tar -xvf *.tar
ccm rcv ....
mv *.tar BACKUP
but after I do the first cadenv <env> , I am unable to execute any of the later commands .
... (6 Replies)
Hi,
I am new to unix and using linux 7.2. I would like to create a script that would make it easyer for me to run my java programms. At the moment I have to type java myJavaprogram
I am trying to write a script that will allow me to type something like this "myscript myJavaprogram" or maybe... (4 Replies)
Hello gurus,
I have three korn shell script 3.1, 3.2, 3.3. I would like to call three shell script in one shell script.
i m looking for something like this
call 3.1;
If 3.1 = "complete" then
call 3.2;
if 3.2 = ''COMPlete" then
call 3.3;
else
exit
The... (1 Reply)
basically i'm tired of hitting the left arrow a few dozen times when correcting a mistake or modifying a history command
i'd like to use vim style key shortcuts while on the command line so that a 55 moves the cursor 55 places to the left...
and i want all the other vi goodies, search of... (3 Replies)
Dear Friends,
Please help me on this
my script name is send.csh
In this i have written the statement like this
set args = ( city state country price )
I want to pass this array to another c shell called receiver.csh. and i want to use it in this c shell
or
how to pass to... (2 Replies)