2 posts tagged with "sed"

Sometimes you just want to extract a single BLOB from a DB2 database... you don't want to write any software... you don't want to pull out some scripting language with a true DB2 database driver binding... you just want to get a BLOB from the database, and write it to a file - using nothing but the command line.

Well, there are two ways, that I know of, to do so. The first one, is the officially "correct" method, and should always work. The second method is even easier, but only works for very small BLOBs (which is all you need sometimes).

There are many ways to determine local IP addresses on Linux platforms. They almost always involve piping ifconfig into a number of grep, awk, cat, and/or tr commands.

Well, my new favorite approach is to pipe ifconfig into a single sed command :)

ifconfig | sed -n -e 's/:127\.0\.0\.1 //g' -e 's/ *inet addr:\([0-9.]\+\).*/\1/gp'

Neat, huh?! :)

So, how does it work? Well, there are two filters (aka scripts, ie the parameters after the -e flags). The first one, 's/:127\.0\.0\.1 //g', simply strips out all occurrences of the local loopback address (127.0.0.1) - this can be left out if you want to include the loopback address in the results. And the second filter, 's/ *inet addr:\([0-9.]\+\).*/\1/gp' matches all lines with IP addresses, strips all but the IP address itself, and prints the matching line (note the p at the end of the filter, which works in with the -n flag at the start of the sed command).