Implement if statement in mail command

hatfani · 02-13-2020, 07:17 AM

Dear all,

Every day I create a mynumbers.csv file which including numbers, for example:
09976543
09976542
09976541

some days it's empty.
I want a script to print the csv file only if it has numbers inside and send it to my mail.
So I built a little script that will print the csv file only if it's more than 0 bytes:

Code:

a=$/my_destination/mynumbers.csv

if [ -s $a ]; then
echo My files: &&cat $a
fi

the thing is that I want to implement it inside my mail command without creating a txt file. I want something like that:

Code:

echo (print the csv file according the if statement) | mail -s "mine" myemail@gmail.com

I know I can make it like that:

Code:

echo my files: $a | mail -s "mine" myemail@gmail.com

but then when the file is empty (it has one empty line) it prints that one empty line and thenit makes one line space which I don't want and makes me crazy.
I thought I could some how take the if command and make it as a variable, but I didn't manage, and I didn't find anywhere that it's possible. maybe someone has another suggestion?

berndbausch · 02-13-2020, 07:39 AM

Why don't you put the echo ... | mail command in the if [ -s $a ]?

Alternatively, you can use echo $( any command pipeline ) | mail.

hatfani · 02-13-2020, 07:56 AM

Quote:

Originally Posted by berndbausch

Why don't you put the echo ... | mail command in the if [ -s $a ]?

Alternatively, you can use echo $( any command pipeline ) | mail.

Because I have more things in the email that I want to add in the Echo command.

berndbausch · 02-13-2020, 08:12 AM

Well, add these things inside the if...then branch. This way you are certain that the numbers file is not empty.

hatfani · 02-13-2020, 09:10 AM

Quote:

Originally Posted by berndbausch

Well, add these things inside the if...then branch. This way you are certain that the numbers file is not empty.

I don't know what is branch...? do you have any links for explanation?

berndbausch · 02-13-2020, 04:04 PM

An if has a then branch and, optionally, an else branch.

Code:

if [ -s mynumbers.csv ]
then
  echo $(echo other text; cat mynumbers.csv) | mail hatfani
fi

Perhaps better:

Code:

if [ -s mynumbers.csv ]
then
  echo other text | cat - mynumbers.csv | mail hatfani
fi

or

Code:

if [ -s mynumbers.csv ]
then
  echo text1 > tempfile
  cat mynumbers.csv >> tempfile
  echo text2 >> tempfile
  mail hatfani < tempfile
fi

MadeInGermany · 02-16-2020, 02:28 AM

A code block you can redirect from/to a file, and connect to a pipe.
Connect the if-fi block to a pipe:

Code:

if [ -s "$a" ]; then
  echo "My files:"
  cat "$a"
fi | mail ...

For demonstration - does not make good sense here.

Connect an explicit { block } to a pipe:

Code:

if [ -s "$a" ]; then
  {
  echo "My files:"
  cat "$a"
  } | mail ...
fi

Also a ( sub shell ) is a code block.
Variables defined in a sub shell are lost in the main shell.
If a { block } is connected to a pipe then the shell automatically converts it to a sub shell.

Perhaps you want to go for a { block } that contains the if-fi...