It seems I am learning something new everyday here at my new
job.
And it always seems no matter how long you have been doing
Unix command line you learn something new you should have known years ago.
This post is about such a thing I feel I should have known a
long time ago.
I got an instant message from a fellow employee to the group
telling us all to run a simple command line program to fix an issue. I won't go into the particulars but the one
line was several Unix commands separated by a semicolon and it ended with a cd
-
This cd - caught my attention I had never seen or used it
before. So I tested it out a bit and
googled for it and found http://mylinuxbook.com/20-interesting-and-extremely-helpful-linux-command-line-tricks/
[1]
This article will go over cd - as well as pushd and popd.
So what does cd - do?
|
> cd -
|
This will go to the last directory your command line was
last at.
As an example
|
> cd Desktop; ls -alh; cd -
|
This will change to the Desktop directory and then run
another linux command "ls -alh"
then it will return to the previous directory it was at.
Pretty useful
But it has one problem...
what if, throughout your one liner, change the directory several
times? You would have to add a cd - at
the end for each time your changed directories…
Or you could use pushd and popd
With pushd and popd I could run the following command line
one liner to have the same effect as the example above.
|
> pushd .; cd Desktop; ls -alh; popd
|
This works well if you change directories several times
For example
|
> pushd .; cd /var/log/; cat
wifi.log; cd /home/; ls -alh; popd
|
References
[1] 20 interesting and extremely helpful Linux command line tricks
Accessed
08/2014