UNIX / Linux: Shell Scripting With mail Command

Posted on in Categories last updated October 2, 2010

How do I send e-mails from a shell script including file attachments?

The easiest solution is to send email from within shell scripts is mail command as follows. To send a message to one or more people, mail can be invoked with arguments which are the names of people to whom the mail will be sent:

mail -s 'subject' username
mail -s 'subject' vivek@nixcraft.net.in
mail -s 'Duplicate ip detected' -c vivek@nixcraft.net.in  ipadmin@nixcraft.net.in </var/log/ipscan.log
mail -s 'yum update failed' -c vivek@nixcraft.net.in -b  sysadins@groups.nixcraft.net.in </var/log/yum.log
mail -s 'Disk failure'  vivek@nixcraft.net.in < /tmp/message

Where,

  • -s ‘word1 word2’ : Specify subject on command line.
  • -c : Send carbon copies to list of users.
  • -b : Send blind carbon copies to list. List should be a comma-separated list of names.
  • < /path/to/file : Read email body using this /path/to/file.

Method #1: Sending File Attachments

The mail command will not work. You need to use uuencode command to send a binary file called reports.tar.gz:

uuencode reports.tar.gz reports.tar.gz | mail -s "Weekly Reports for $(date)" admin@groups.mgmt.nixcraft.net.in

You can email images or any file using the same format:

uuencode file1.png file1.png | mail -s "Funny" users@groups.nixcraft.net.in

Method #2: File Attachments with mutt Command

The mutt is a MUA (mail user agent) – an email client for text based session. It can be used for reading electronic mail under unix like operating systems, including support color terminals, MIME (attachments), and a threaded sorting mode. You can use mutt command as follows to send email attachments:

mutt -s "Filewall logs" -a /tmp/fw.logs.gz vivek@nixcraft.net.in < /tmp/emailmessage.txt

Tip # 1: Empty Mail Body

To use an empty line as the mail body use special file /dev/null or echo command as follows:

echo | mutt -s 'Subject' -a attachment.tar.gz vivek@nixcraft.net.in
mutt -s 'Subject' -a attachment.tar.gz vivek@nixcraft.net.in </dev/null
mail -s "Disk failed @ $(hostname)" mobilenumber@services.api.nixcraft.net.in </dev/null

Tip #2: Writing Mail Body Using Here documents

The here documents (redirection) tells the shell to read input from the current source (HERE) until a line containg only word (HERE) is seen:

#!/bin/bash
...
....
mail -s "Disk Failed" vivek@nixcraft.net.in<<EOF
NAS server [ mounted at $(hostname) ] is running out of disk space!!!
Current allocation ${_SPACE} @ $(date)
EOF
...
..

Tip # 3: Conditional Mail

Use the if else if and the exit status of a command as follows:

[ $(grep -c -i "hardware error" /var/log/mcelog) -gt 0 ] && { echo "Hardware errors found on $(hostname) @ $(date). See log file for the details /var/log/mcelog." | mail -s "HW Errors" mobilephone@api.nixcraft.net.in ;}

OR

#!/bin/bash
....
.....
# backup dirs using gnu/tar
/usr/bin/tar --exclude "*/proc/*" --exclude "*/dev/*" --exclude '*/cache/*' -zcvf /nas05/backup.tar.gz /var/www/html /home/vivek
 
# send an email if backup failed
if [ $? -ne 0 ] 
then
 /usr/bin/mail -s "GNU/TAR Backup Failed" vivek@nixcraft.net.in<<EOF
GNU/Tar backup failed @ $(date) for $(hostname)
EOF
else
 /usr/bin/logger "Backup done"        
fi
....
..
# clean up
rm $_filename

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

9 comment

  1. good stuff !!!

    it took me months to figure out how to send HTML,
    so here’s hoping this can save some1 else head ache…

    mail -a ‘Content-Type: text/html’ -s “$ERROR” “$EMAIL” << EOF
    NAS server [ mounted at $(hostname) ] is running out of disk space!!!
    Current allocation ${_SPACE} @ $(date)
    EOF

  2. I have tried all the ways, but none of them is working for me. Its throwing error
    mail: invalid option — ‘c’
    Try `mail –help’ or `mail –usage’ for more information.
    I have tried installing mutt and mailutils. But no luck.

    Please help me in getting this error resolved.

  3. It is bizarre that anyone would still suggest using uuencode for mail message attachments when there is an actual standard that specifies how attachments should be included in a mail message. That standard is MIME, and it’s been an Internet standard (RFC 2045) for over 20 years now.

  4. Hi,
    i created a job in jenkins, in s single job am running two builds, one is Ant build that i run through shell script and second by triggering build.In this single build both Ant and further process runs.I am getting mail notifications for final build thats fine.but i need an mail notification for Ant build which i am running by shell script.what Commands should i use to get mail notifc.please any one guid me in that.

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