BASH script segment won't work in larger script

[chalsall]

Originally Posted by kruoli

Are you piping something into the script? Or are you accessing stdin at any place in the script?

I don't personally do any BASH scripting. Everything is Perl...

But I have found that strace can be ***very*** helpful in figuring out what's going on in complex situations like this. Not easy to work with, but it /should/ give you everything you need to know about what's actually going on.

[paulunderwood]

Attach the script for us to debug. Specify which arguments you might be using with the script.

[EdH]

Originally Posted by paulunderwood

Attach the script for us to debug. Specify which arguments you might be using with the script.

Actually, I just wrote a small script that displays the exact behavior between working and not, by un/commenting two lines. The problem is definitely generated globally for the script, by reading a file:

#!/bin/bash

a="31363920 948583258055568 -21094061301960794201597 -101781123694367174730692456309 1859252514529139843616145918243322920 1347307311985305327578340438707291179185984 951738172269489471300643 -167704995415343890580296180142353038"
echo "$a" > testcase
#exec < "testcase"
#read b
c="31363920"
d="${a:0:8}"
e="${b:0:8}"
m="3"

echo "m is $m and d is $d and c is $c and b is ${b:0:10}... and a is ${a:0:10}..."
printf "\nYAFU says $c*$m is "
../../yafu/yafu "expr($c*$m)" -silent
printf "\nYAFU says $d*$m is "
../../yafu/yafu "expr($d*$m)" -silent
printf "\nYAFU says $e*$m is "
../../yafu/yafu "expr($e*$m)" -silent

With the lines commented out:

m is 3 and d is 31363920 and c is 31363920 and b is ... and a is 31363920 9...

YAFU says 31363920*3 is 94091760

YAFU says 31363920*3 is 94091760

YAFU says *3 is wrong number of arguments in *, expected 2
0

This is exactly what should result. But, here's an example of failure (commented lines uncommented):

m is 3 and d is 31363920 and c is 31363920 and b is 31363920 9... and a is 31363920 9...

YAFU says 31363920*3 is no variable indicator (@): interpreting batchfile lines as input expressions
eof; done processing batchfile

YAFU says 31363920*3 is no variable indicator (@): interpreting batchfile lines as input expressions
eof; done processing batchfile

YAFU says 31363920*3 is no variable indicator (@): interpreting batchfile lines as input expressions
eof; done processing batchfile

Note that the file read caused a failure for all YAFU instances.

[EdH]

Originally Posted by chalsall

I don't personally do any BASH scripting. Everything is Perl...

But I have found that strace can be ***very*** helpful in figuring out what's going on in complex situations like this. Not easy to work with, but it /should/ give you everything you need to know about what's actually going on.

I've tried to use strace in the past and would need to be more familiar with it for any successful results. It might come to that.

[kruoli]

Originally Posted by EdH

The problem is definitely generated globally for the script, by reading a file.

Ah! This definitely matches what I got from reading the code. Since you are reading from a file, isatty is 0. But since the file is read until the end, YAFU cannot extract any more lines, ignores the command line since it does not contain an @ and simply exits. The problem is that YAFU will always work that way when a piped input file is detected.

It is not a problem of bash, it only passes the information of not being connected to stdin to the YAFU process.

You could work around that by modifying driver.c according to my last post (e.g. commenting out the part where is_cmdlinerun gets set to 2 and instead inserting something like printf("WARNING: custom build, automatic stdin batch file detection disabled.\n"); to save you from running into the opposite problem in the future at some point.

[paulunderwood]

am=3
c4=2346021463111956
      echo "c4 is $c4 and am is $am"
      c4m=$(echo "expr($c4*$am)")
      echo "c4 is $c4 and c4m is $c4m"
      c4m=$(factor $(expr $c4 \* $am))
      echo "c4 is $c4 and c4m is $c4m"

Works!

[EdH]

Originally Posted by kruoli

Ah! This definitely matches what I got from reading the code. Since you are reading from a file, isatty is 0. But since the file is read until the end, YAFU cannot extract any more lines, ignores the command line since it does not contain an @ and simply exits. The problem is that YAFU will always work that way when a piped input file is detected.

It is not a problem of bash, it only passes the information of not being connected to stdin to the YAFU process.

You could work around that by modifying driver.c according to my last post (e.g. commenting out the part where is_cmdlinerun gets set to 2 and instead inserting something like printf("WARNING: custom build, automatic stdin batch file detection disabled.\n"); to save you from running into the opposite problem in the future at some point.

Ok, this is starting to make sense, then, since I'm trying to call YAFU while reading lines from an open file. You're saying YAFU is simply noting that a file is open, but not recognizing it is not a batchfile. I think the solution which I am now employing is my best option. I'm simply accepting the extra notes from YAFU and parsing out the wanted value. That way, I'm not changing anything in the YAFU code, that will be changed back with future pulls.

Thanks!

[EdH]

Originally Posted by paulunderwood

am=3
c4=2346021463111956
      echo "c4 is $c4 and am is $am"
      c4m=$(echo "expr($c4*$am)")
      echo "c4 is $c4 and c4m is $c4m"
      c4m=$(factor $(expr $c4 \* $am))
      echo "c4 is $c4 and c4m is $c4m"

Works!

This doesn't work in the posted script:

YAFU says 31363920*3 is unrecognized variable or function 'factor94091760'

or:

YAFU says 31363920*3 is unrecognized character in input: -1

Thanks!

[paulunderwood]

Originally Posted by EdH

This doesn't work in the posted script:

YAFU says 31363920*3 is unrecognized variable or function 'factor94091760'

or:

YAFU says 31363920*3 is unrecognized character in input: -1

Thanks!

Of course not. I substituted ../../yafu/yafu with factor. You'll have to rectify it.

[EdH]

Originally Posted by paulunderwood

Of course not. I substituted ../../yafu/yafu with factor. You'll have to rectify it.

I'm missing something. I'm really tall, but somethings is just going right over my head.

[paulunderwood]

Here is what you should test:

am=3
c4=2346021463111956
      echo "c4 is $c4 and am is $am"
      c4m=$(echo "expr($c4*$am)")
      echo "c4 is $c4 and c4m is $c4m"
      c4m=$(../../yafu/yafu $(expr $c4 \* $am) -silent)
      echo "c4 is $c4 and c4m is $c4m"

Note the spaces around the operator \* in expr; They are important delimiters. Also note that * has to be escaped with \, otherwise it will be wildcard for files in the current directory.