Complex alias in bash

[sweyhrich]

I was online with my dialup connection and found things running really slowly. I decided it was time to do a restart, and iTunes announced to me that someone was connected to my shared iTunes library! At home on my Airport network I've just left this on, for the sake of others in the house who want to connect from time to time, but I'd never come across who sniffed my iTunes library over the dialup before.

Anyway, in perusing the hints, I found one that lets me see who is connected (I'd like to know next time), and this is the code:

netstat -f inet -W | awk '$4 ~ /3689/ {print "iTunes connection from: "$5}' \
 | sed -e 's/\.[^.]*$//g'

However, in trying to make this into an alias for bash, I found that

alias itunesshare="netstat -f inet -W | awk '$4 ~ /3689/ {print "iTunes connection from: "$5}' \
  | sed -e 's/\.[^.]*$//g'"

doesn't work because part of the line I am trying to make into an alias already contains the double quote, as well as the single quote. (Even if I leave out the "\" to do it on two lines). Is there a way to make this work?

(There was a downloadable script on that hint page, but it was from May 2003, and the link is no longer valid).

[hayne]

1) escape the embedded single quotes with backslashes: \'

2) make this into a bash "function" instead of an "alias". Aliases are intended only for relatively simple things.

3) make it a bash script by saving the command (not the alias) to a file, making the first line
#!/bin/sh
and making the fiel executable.

[sweyhrich]

Quote: Originally posted by hayne 3) make it a bash script by saving the command (not the alias) to a file, making the first line #!/bin/sh and making the fill executable.

So I put that line in my first message in a file by itself, with the first line of the file being the "#!/bin/sh", and the second line the command.

Where do I put such a file, and how do I make it executable?

[zed]

Where to put the file ???

Well most UNIX people create a dir in their home folders called: bin

mkdir bin

then edit your path to include this directory..or just call the file directly

now to make it executable:

chmod is ya friend here

chmod 755 <filename>

Will do the trick

so now to run the file

~/bin/<filename>

the ~ is replaced automatically with ya home folder path...

Cheers,
--Zed

[gatorparrots]

Quote: Originally posted by hayne 3) make it a bash script by saving the command (not the alias) to a file, making the first line #!/bin/sh

To be a bash script, shouldn't the first line be
#!/bin/bash
(I know bash is used to provide /bin/sh under Panther, but you don't want to impose Bourne shell limitations on yourself unnecessarily...)

[sweyhrich]

Quote: Originally posted by zed Where to put the file ??? (and comments following)

Thanks, that worked.

Quote: Originally posted by gatorparrots To be a bash script, shouldn't the first line be #!/bin/bash

I notice it works either way. Why is either necessary, and why would one be preferred?

[acme.mail.order]

the `#!` operator tells the operating system to execute the following code with the specified program. `/bin/sh` is the path to the original Bourne shell interpreter. `/bin/bash` is the path to the Bourne Again SHell. If you write a perl program, you set it to `/usr/bin/perl` or wherever perl is on your computer.

Your script is simple enough that it will run under sh, bash, tcsh or almost any other shell. More complex scripts are not so flexible.

[sweyhrich]

Thanks for the explanation. As always, the answer and associated comments have been educational!