BASH script segment won't work in larger script

[EdH]

Originally Posted by 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.

However, as proven in the supplied script, neither is necessary for the call to succeed:

../../yafu/yafu "expr($c*$m)" -silent

works just fine as long as I haven't opened a file, and spaces and \*, as well as original fail, if I have opened a file. BTW, spaces are accepted by YAFU, but "\*" is not.

[paulunderwood]

Originally Posted by EdH

However, as proven in the supplied script, neither is necessary for the call to succeed:

../../yafu/yafu "expr($c*$m)" -silent

works just fine as long as I haven't opened a file, and spaces and \*, as well as original fail, if I have opened a file. BTW, spaces are accepted by YAFU, but "\*" is not.

I have

c4m=$(../../yafu/yafu $(expr $c4 \* $am) -silent)

You have

cm4=$(../../yafu/yafu "expr($c*$m)" -silent)

Do you see my extra $ for expr?

[kruoli]

Wait, that's doing two fully different things!

There is expr of GNU coreutils (as in $(expr 2 \* 2)) and there is the YAFU function expr (as in expr(2*2) or ./yafu "expr(2*2)").

Edit: Executing something like ./yafu $(expr $var1 \* $var2) is like executing ./yafu 15, e.g. calling yafu only with a constant. GNU expr is already evaluating, so var1=$(var2 \* var3) or var1=$((var1*var2)) should be sufficient. I'm not sure up to which limit the latter one works.

[paulunderwood]

Originally Posted by kruoli

Wait, that's doing two fully different things!

There is expr of GNU coreutils (as in $(expr 2 \* 2)) and there is the YAFU function expr (as in expr(2*2) or ./yafu "expr(2*2)").

I'm not familiar with yafu. Shoud the quotes be escaped for yafu's expr in a bash expression?

[kruoli]

Basically, the specific problem was that the command line was ignored by YAFU in the script because of redirecting a file. The syntax was okay in all cases.

[EdH]

Originally Posted by paulunderwood

I'm not familiar with yafu. Shoud the quotes be escaped for yafu's expr in a bash line?

YAFU expects

./yafu "expr(number*number)" <options>

for its "expr()" call. The quotes tell YAFU the function (in this case expr) to invoke. Then the <options> are added outside the quotes.

[paulunderwood]

Originally Posted by EdH

YAFU expects

./yafu "expr(number*number)" <options>

for its "expr()" call. The quotes tell YAFU the function (in this case expr) to invoke. Then the <options> are added outside the quotes.

And what happens with:

cm4=$(../../yafu/yafu \"expr($c*$m)\" -silent)

?

[EdH]

Originally Posted by paulunderwood

And what happens with:

cm4=$(../../yafu/yafu \"expr($c*$m)\" -silent)

?

Without file read:

YAFU says 31363920*3 is ytestW-N.sh: command substitution: line 15: syntax error near unexpected token `('
ytestW-N.sh: command substitution: line 15: `../../yafu/yafu \"expr($c*$m)\" -silent)'

With file read:

YAFU says 31363920*3 is ytestW-N.sh: command substitution: line 15: syntax error near unexpected token `('
ytestW-N.sh: command substitution: line 15: `../../yafu/yafu \"expr($c*$m)\" -silent)'

no variable indicator (@): interpreting batchfile lines as input expressions
 eof; done processing batchfile

Edit 2: These are the lines as edited into the above script:

cm4=$(../../yafu/yafu \"expr($c*$m)\" -silent)
echo $cm4

[paulunderwood]

One last thing to try:

cm4=$(../../yafu/yafu \"expr($c\*$m)\" -silent)

Then I'll d/l YAFU

[EdH]

Originally Posted by paulunderwood

One last thing to try:

cm4=$(../../yafu/yafu \"expr($c\*$m)\" -silent)

Then I'll d/l YAFU

YAFU says 31363920*3 is ytestW-N.sh: command substitution: line 15: syntax error near unexpected token `('
ytestW-N.sh: command substitution: line 15: `../../yafu/yafu \"expr($c\*$m)\" -silent)'

You would have to build YAFU, which would take a little bit. Unless you'd really like to pursue this, I'm OK with my current work around, which parses out the wanted result, from all the extra.

[paulunderwood]

#!/bin/bash

a="31363920 948583258055568 -21094061301960794201597 -101781123694367174730692456309 1859252514529139843616145918243322920 1347307311985305327578340438707291179185984 951738172269489471300643 -167704995415343890580296180142353038"
echo "$a" > testcase
#exec < "testcase"
read b < testcase 
c="31363920"
d="${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

results in:

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 94091760

YAFU says 31363920*3 is 94091760

YAFU says 31363920*3 is 94091760

Idea lifted from https://linuxhint.com/read_file_line_by_line_bash/

(I compiled msieve for YAFU without zlib.)