bash scripting: until eof

andrew123456 · 2009-04-21 19:54:19

hey guys, i was hoping for some help. i need to make a script that will constantly add read numbers together until ctrl-d (end of file) is sent. i've got the basic adding part done, but i can't get the until eof part to work, as i have no idea what the eof character is.

here's what i've got:

#!/bin/bash

a=0
until >> eof #this line doesn't work :(
do 
read b
a=$(($b+$a))
echo "new number is $a"
done

it's the until >> eof line that i baisically made up because i don't know what it is i need there.
any suggestions?

Procyon · 2009-04-21 20:05:02

Like this?

a=0
while read b; do a=$(($b+$a)); echo $a is new; done

kumyco · 2009-04-21 20:09:09

#!/bin/bash

a=0
while read b #this line doesn't work :(
do 
a=$(($b+$a))
echo "new number is $a"
done

you can also replace #!/bin/bash by #!/bin/sh nothing bash specific about that script as it stands

andrew123456 · 2009-04-21 20:14:55

wow thanks guys, i knew it was an obvious thing that i was missing, thanks for the help.

sidenote; what's the difference between /bin/bash and /bin/sh, is there a disadvantage to putting it over /bin/sh?

kumyco · 2009-04-21 20:18:38

allows it to be run other shells /bin/sh might point to e.g dash or ksh for someone else

andrew123456 · 2009-04-21 20:28:47

greeat, thanks guys! i appreciate it!

.:B:. · 2009-04-21 21:30:24

[stijn@hermes ~]$ ll /bin/sh
lrwxrwxrwx 1 root root 4 jan 28 20:35 /bin/sh -> bash

Sh = symlink to the default shell.

tam1138 · 2009-04-22 22:52:24

B wrote:

Sh = symlink to the default shell.

I hope not. It should only ever link to shells which feature a superset of /bin/sh functionality (ie, not csh and derivatives).

rson451 · 2009-04-22 23:21:32

Interestingly enough, I had to fix some broken shit at work today because of this. Some old scripts were using #!/bin/sh, but using bashisms. The scripts were moved over to a ubuntu server which has /bin/sh -> /bin/dash and hence were no longer working.

karol · 2009-05-12 23:42:42

rson451 wrote:

Interestingly enough, I had to fix some broken shit at work today because of this. Some old scripts were using #!/bin/sh, but using bashisms. The scripts were moved over to a ubuntu server which has /bin/sh -> /bin/dash and hence were no longer working.

You probably know the quote that it's easier to port a shell than a script, so I'm wandering, how did you fix the situation - installed bash & symlinked?

rson451 · 2009-05-12 23:51:28

Bash was installed, and it wasn't many scripts so I just changed the shebangs.

Arch Linux

#1 2009-04-21 19:54:19

bash scripting: until eof

#2 2009-04-21 20:05:02

Re: bash scripting: until eof

#3 2009-04-21 20:09:09

Re: bash scripting: until eof

#4 2009-04-21 20:14:55

Re: bash scripting: until eof

#5 2009-04-21 20:18:38

Re: bash scripting: until eof

#6 2009-04-21 20:28:47

Re: bash scripting: until eof

#7 2009-04-21 21:30:24

Re: bash scripting: until eof

#8 2009-04-22 22:52:24

Re: bash scripting: until eof

#9 2009-04-22 23:21:32

Re: bash scripting: until eof

#10 2009-05-12 23:42:42

Re: bash scripting: until eof

#11 2009-05-12 23:51:28

Re: bash scripting: until eof

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