Commands by virtualshock (5)

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How many files in the current directory ?
A simple "ls" lists files *and* directories. So we need to "find" the files (type 'f') only. As "find" is recursive by default we must restrict it to the current directory by adding a maximum depth of "1". If you should be using the "zsh" then you can use the dot (.) as a globbing qualifier to denote plain files: zsh> ls *(.) | wc -l for more info see the zsh's manual on expansion and substitution - "man zshexpn".

check open ports without netstat or lsof

Show linux kernel modules dependencies
Use modprobe to list all the dependencies of a certain kernel module. Handy when debugging system issues.

revert a committed change in SVN
This command can be used to revert a particular changeset in the local copy. I find this useful because I frequently import files into the wrong directory. After the import it says "Committed revision 123" or similar. to revert this change in the working copy do: svn merge -c -123 . (don't forget the .) and then commit.

Realtime lines per second in a log file, with history
This is similar to standard `pv`, but it retains the rate history instead of only showing the current rate. This is useful for spotting changes. To do this, -f is used to force pv to output, and stderr is redirected to stdout so that `tr` can swap the carriage returns for new lines. (doesn't work correctly is in zsh for some reason. Tail's output isn't redirected to /dev/null like it is in bash. anyone know why? ???????)

Every Nth line position # (SED)
sed extract every nth line. Generic is: $ sed -n 'STARTPOSITION,${p;n;*LINE}' foo where n;*LINE = how many lines. thus p;n;n; is "for every 3 lines" and p;n;n;n;n; is "for every 5 lines"

IBM AIX: Extract a .tar.gz archive in one shot

List just the executable files (or directories) in current directory
A bit shorter ;)

Daemonize nc - Transmit a file like a http server
Allow to launch nc like a daemon, in background until you still stop it. You can stop it with kill %1 (jobs method) or kill PID. The -k option can force nc to listen another connection, but if you use redirection, it will work only one time. The loop's inside doesn't do anything, but we can imagine to send a message to screen when a connection is established

ubuntu tasksel
The command tasksel allows the choice of packages from the command line to get predefined configurations for specific services (usually this option is offered during installation).

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