Archive for the ‘linux/unix’ Category
*nix: Comparing two files
Everybody knows about diff.
I read about sdiff today for side by side diff.
Here is the one I found useful in some cases but I forget it so I am saving it here:
NAME
cmp – compare two files
SYNOPSIS
cmp [-l | -s] file1 file2 [skip1 [skip2]]
DESCRIPTION
The cmp utility compares two files of any type and writes the results to
the standard output. By default, cmp is silent if the files are the
same; if they differ, the byte and line number at which the first differ-
ence occurred is reported.
May be I will add some examples to show the difference but later.
*nix: nslookup to resolve an IP to host name
nslookup is useful to resolve an ip address to a host name in the linux/unix environment.
nslookup – query Internet name servers interactively
Ruby : Where are the gems on ubuntu 7.04
It took me some time to figure it out where the gems are installed on my ubuntu 7.04 linux machine so I thought I would save it here as a reminder. The ruby gems are stored here:
/var/lib/gems/1.8/gems
What I did to find this is to run gem install without sudo to see the error message:
me@desktop:/usr/lib/ruby/1.8$ gem install rails Bulk updating Gem source index for: http://gems.rubyforge.org ERROR: While executing gem ... (Errno::EACCES) Permission denied - /var/lib/gems/1.8/cache/rails-1.2.3.gem
The permission denied message gave me my answer. Who said error messages are not educational?
Hurray!
