The Linux command line can be very powerful once you know how to use it. You can parse data, monitor processes, and do a lot of other useful and cool things using it. There often comes a need to generate a report and mail it out. It could be as simple a requirement as a notification that the day\u2019s backup went through fine, or did not. I\u2019ll help you get started with sending mails from the Linux command line and in shell scripts. We will also cover sending attachments from the command line. We will begin with the \u201cmail\u201d command.
\nMAIL<\/p>\n
First run a quick test to make sure the \u201csendmail\u201d application is installed and working correctly. Execute the following command, replacing \u201cyou@youremailid.com\u201d with your e-mail address.<\/p>\n
# mail -s \u201cHello world\u201d you@youremailid.com<\/p>\n
Hit the return key and you will come to a new line. Enter the text \u201cThis is a test from my server\u201d. Follow up the text by hitting the return key again. Then hit the key combination of Control+D to continue. The command prompt will ask you if you want to mark a copy of the mail to any other address, hit Control+D again. Check your mailbox. This command will send out a mail to the email id mentioned with the subject, \u201cHello world\u201d.<\/p>\n
To add content to the body of the mail while running the command you can use the following options. If you want to add text on your own:<\/p>\n
# echo \u201cThis will go into the body of the mail.\u201d | mail -s \u201cHello world\u201d you@youremailid.com<\/p>\n
And if you want mail to read the content from a file:<\/p>\n
# mail -s \u201cHello world\u201d you@youremailid.com < \/home\/calvin\/application.log\n\nSome other useful options in the mail command are:\n\n-s subject (The subject of the mail)\n-c email-address (Mark a copy to this \u201cemail-address\u201d, or CC)\n-b email-address (Mark a blind carbon copy to this \u201cemail-address\u201d, or BCC)\n\nHere\u2019s how you might use these options:\n\n# echo \u201cWelcome to the world of Calvin n Hobbes\u201d | mail -s \u201cHello world\u201d calvin@cnh.com -c hobbes@cnh.com -b susie.derkins@cnh.com\nMUTT\n\nOne of major drawbacks of using the mail command is that it does not support the sending of attachments. mutt, on the other hand, does support it. I\u2019ve found this feature particularly useful for scripts that generate non-textual reports or backups which are relatively small in size which I\u2019d like to backup elsewhere. Of course, mutt allows you to do a lot more than just send attachments. It is a much more complete command line mail client than the \u201cmail\u201d command. Right now we\u2019ll just explore the basic stuff we might need often. Here\u2019s how you would attach a file to a mail:\n\n# echo \u201cSending an attachment.\u201d | mutt -a backup.zip -s \u201cattachment\u201d calvin@cnh.com\n\nThis command will send a mail to calvin@cnh.com with the subject (-s) \u201cattachment\u201d, the body text \u201cSending an attachment.\u201d, containing the attachment (-a) backup.zip. Like with the mail command you can use the \u201c-c\u201d option to mark a copy to another mail id.\nSENDING MAIL FROM A SHELL SCRIPT\n\nNow, with the basics covered you can send mails from your shell scripts. Here\u2019s a simple shell script that gives you a reading of the usage of space on your partitions and mails the data to you.\n\n #!\/bin\/bash\n df -h | mail -s \u201cdisk space report\u201d calvin@cnh.com\n\nSave these lines in a file on your Linux server and run it. You should receive a mail containing the results of the command. If, however, you need to send more data than just this you will need to write the data to a text file and enter it into the mail body while composing the mail. Here\u2019s and example of a shell script that gets the disk usage as well as the memory usage, writes the data into a temporary file, and then enters it all into the body of the mail being sent out:\n\n #!\/bin\/bash\n df -h > \/tmp\/mail_report.log
\n free -m >> \/tmp\/mail_report.log
\n mail -s \u201cdisk and RAM report\u201d calvin@cnh.com < \/tmp\/mail_report.log\n\nNow here\u2019s a more complicated problem. You have to take a backup of a few files and mail then out. First the directory to be mailed out is archived. Then it is sent as an email attachment using mutt. Here\u2019s a script to do just that:\n\n #!\/bin\/bash\n tar -zcf \/tmp\/backup.tar.gz \/home\/calvin\/files\n echo | mutt -a \/tmp\/backup.tar.gz -s \u201cdaily backup of data\u201d calvin@cnh.com\n\nThe echo at the start of the last line adds a blank into the body of the mail being set out.\n\nThis should get you started with sending mails form the Linux command line and from shell scripts. Read up the \u201cman page\u201d for both mail and mutt for more options.\n<\/p>\n","protected":false},"excerpt":{"rendered":"
The Linux command line can be very powerful once you know how to use it. You can parse data, monitor processes, and do a lot of other useful and cool things using it. There often comes a need to generate a report and mail it out. It could be as simple a requirement as a… <\/p>\n