send email from terminal bad behaviour

Question

I have the following script that i put togheter from the web, to send emails from terminal trough gmail.

#!/bin/bash

#sendGmail "FROM" "TO" "SUBJECT" "BODY" "ATTACHMENTS (optional)"
FROM=$1
TO=$2
SUBJECT=$3
BODY=$4

# Function to check if entered file names are really files
function check_files()
{
output_files=""
for file in $1; do
    if [ -s $file ]; then
        output_files="${output_files}${file} "
    fi
done
echo $output_files
}

if [ "$FROM" == "" ]; then
    FROM="[email protected]"
else    
     if [[ "$FROM" =~ "^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$" ]]; then
        echo error in FROM
        exit
    fi
fi

if [[ "$TO" =~ "^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$" ]]; then
    echo error in TO
    exit
fi

if [ -z "$5" ]; then
    echo $BODY | mail -r $FROM -s $SUBJECT $TO
else
    ATT=$5
    ATTACHMENTS=""
    attachments=$(check_files "$ATT")
    for attachment in $attachments; do
        ATTACHMENTS="$ATTACHMENTS $attachment"
    done
    echo $ATTACHMENTS

    echo $BODY | mail -r $FROM -s $SUBJECT -A $ATTACHMENTS $TO
fi

echo email sent!

But when i send emails, i have the following behaviours:

• with/without attachments: If $subject is "some random theme", then the email is sent to $TO and [email protected], [email protected] and theme@ mipc.localdomain.
• without attachments: $BODY is in the email body
• with attachments: email body is empty

EDIT: thanks to @ilkkachu, first issue was fixed, new code:

#!/bin/bash

#sendGmail "FROM" "TO" "SUBJECT" "BODY" "ATTACHMENTS (optional)"
FROM=$1
TO=$2
SUBJECT=$3
BODY=$4

if [ "$FROM" == "" ]; then
    FROM="[email protected]"
else    
     if [[ "$FROM" =~ "^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$" ]]; then
        echo error in FROM
        exit
    fi
fi

if [[ "$TO" =~ "^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$" ]]; then
    echo error in TO
    exit
fi

if [ -z "$5" ]; then
    echo "$BODY" | mail -r "$FROM" -s "$SUBJECT" "$TO"
else
    ATT=$5
    ATTACHMENTS=""
    for attachment in $ATT; do
        if [ -f $attachment ]; then
            ATTACHMENTS="$ATTACHMENTS-A $attachment "
        else
            echo something wrong with $attachment, therefore not attached
        fi  
    done

    echo "$BODY" | mail -r "$FROM" -s "$SUBJECT" $ATTACHMENTS "$TO"
fi

echo email sent!

Answer 1

That's because of word splitting. If SUBJECT contains some random theme, then mail -s $SUBJECT is the same as mail -s some random theme. The contents of $subject is split to words on the whitespace. You need to use quotes: mail -s "$SUBJECT".

About the attachments, you probably need to add the -A option for each file, so instead of -A file1 file2, you may need -A file1 -A file2. If your filenames don't contain whitespace, you could do that by adding the -A in ATTACHMENTS for each filename, e.g.: ATTACHMENTS="$ATTACHMENTS -A $attachment" and then use $ATTACHMENTS by itself on the mail command (you don't want quotes here, since the option and file names need to be split).

The proper way would of course be to use an array to hold the command line arguments, but your for loop already causes word splitting on the attachments, so an array wouldn't help.

So:

for f in files... ; do
    ATTACHMENTS="-A $f"
done
echo "$BODY" | mail -r "$FROM" -s "$SUBJECT" $ATTACHMENTS "$TO"

I'll also assume you've checked your mail uses -A to take attachments. There are a number of versions of mail, and the ones I found don't know that option. E.g. the one whose man page is on die.net takes -a for attachments, and uses -A for something else. So, you may want to double check that if it doesn't work.