[ydl-gen] Sending mail from the command line

[Eric Dunbar]

On 08/09/06, Joseph E. Sacco, Ph.D. <joseph_sacco at comcast.net> wrote:
> Eric,
>
> "> /dev/null 2>&1 " takes any output directed to stdout or stderr and
> redirects it to the bit bucket, /dev/null.
>
> Specifically:
> * redirect stdout to /dev/null
>
>    > /dev/null
>
> * redirect stderr to stdout
>
>    2>&1

Q1:
So, since it's redirected to a 'bit bucket' (euphemism for garbage
can?), does this mean that nothing happens with the redirected
information?

Q2:
Also, where are the stdout and stderr coming from? From the first
command (the ls in this case) or from the second command?

Q3:
In '2>&1':
1. the '2' represents the 'stderr' from ls (or from both)?,
2. the '>' represents 'redirect', and
3. the '&1' means append to 1. What is 1? The first argument passed to
the current command (in this case mail)?

> A construct like this is often used in a crontab entry.
>
> -Joseph

<snip>

> If you use a construct like this in a crontab file, you

Your thought process ended abruptly?

Thanks for the edumacational posts -- I'm learning lots,

Eric.

> On Fri, 2006-09-08 at 23:17 -0400, Eric Dunbar wrote:
> > On 07/09/06, Joseph E. Sacco, Ph.D. <joseph_sacco at comcast.net> wrote:
> > > Of course, a pipe should work, assuming sendmail is running. Here is an
> > > example:
> > >
> > >     % ls | mail -s "output of ls"  jsacco > /dev/null 2>&1
> >
> > Question time:
> >
> > What does the "> /dev/null 2>&1" do?
> >
> > I understand that the | is the 'pipe' and it redirects the output from
> > the first command to the input for the second but what do the
> > following arguments do?:
> > '>'
> > '/dev/null 2'
> > '>&1'
> >
> > When I try:
> > ls | mail -s "output of ls"  username > /dev/null 2>&1
> >
> > and
> >
> > ls | mail -s "output of ls"  username
> >
> > I get the same e-mail with either command.
> >
> > Thanks, Eric.