bashrc produced unexpected results

[zaphod_es]

Creating an alias for my ssh command to my proxy server I added the line like this line to ~/.bashrc

alias linkname=`ssh -D 7777 -p 2299 username@example.com`

Then to test it I fired up a new shell and, to my suprise, after a second or two of delay, it showed a login screen for my server at example.com. Confused I remarked out the new line and started another new shell. This did the expected thing and showed a local login screen. Examination of my new line in .bashrc showed that I had used backticks instead of single quotes. I changed the entry to
alias linkname='ssh -D 7777 -p 2299 username@example.com'
This now works as I intended and logs me into the remote server.

Can someone explain what happened and why? Are backticks part of the syntax for an alias? Are there any interesting tricks I can use with them?

[schragge]

Backticks are used for command substitution in shell. The newer form of the same is $(...)
See
http://www.gnu.org/software/bash/man...stitution.html
http://tldp.org/LDP/abs/html/commandsub.html
http://wiki.bash-hackers.org/syntax/expansion/cmdsubst

[zaphod_es]

Thanks, I sort of knew about command substitution but had not realised that, in effect, .bashrc is a script and runs commands.