It took me ages to learn bash redirection properly, and I still have to concentrate sometimes to keep my &s and my >s straight. Here's the lowdown in case you, too, have intermittent brain failure on this one.

The Linux utility awk can create output redirection for data you want to save and it can use input redirection from commands or respond interactively with users.

It took me ages to learn bash redirection properly, and I still have to concentrate sometimes to keep my &s and my >s straight. Here's the lowdown in case you, too, have intermittent brain failure on this one. Bash has three standard file descriptors: stdin, stdout and stderr, which refer respectively to input, output and error output.

In addition to the fairly common forms of input/output redirection the shell recognizes something called process substitution. Although not documented as a form of input/output redirection, its syntax and its effects are similar.

So considering that compiz++ is now master and my patches haven’t been maintained in a while, a lot of you might be wondering what is going on with input redirection and MPX.

If you're using Sudo, you've probably already discovered that the increased privileges apply only to the first command typed and don't extend to any input or output redirection.

If you're using Sudo, you've probably already discovered that the increased privileges apply only to the first command typed and don't extend to any input or output redirection.

Following bellow is attempt to reproduce Hans de Goede blog entry at http://planet.spice-space.org/ on Ubuntu 11.10 with intent to build Qemu-kvm 0.15.0 with usb redirection network support per http://planet.spice-space.org/ via git repository git://people.freedesktop.org/~jwrdegoede/qemu.

Everybody's seen redirection in bash commands, that's pretty common, but bash also allows you to define redirections when you define functions. This causes the redirections to be evaluated/executed whenever the function is called. This feature doesn't really give you any new features, just another way to express existing features.