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WHAT'S NEW?

Mar 01: Michael Sanders demos an X-windows GUI for AWK.

Mar 01: Awk100#24: A. Lahm and E. de Rinaldis' patent search, in AWK

Feb 28: Tim Menzies asks this community to write an AWK cookbook.

Feb 28: Arnold Robbins announces a new debugger for GAWK.

Feb 28: Awk100#23: Premysl Janouch offers a IRC bot, In AWK

Feb 28: Updated: the AWK FAQ

Feb 28: Tim Menzies offers a tiny content management system, in Awk.

Jan 31: Comment system added to awk.info. For example, see discussion bottom of ?keys2awk

Jan 31: Martin Cohen shows that Gawk can handle massively long strings (300 million characters).

Jan 31: The AWK FAQ is being updated. For comments/ corrections/ extensions, please mail tim@menzies.us

Jan 31: Martin Cohen finds Awk on the Android platform.

Jan 31: Aleksey Cheusov released a new version of runawk.

Jan 31: Hirofumi Saito contributes a candidate Awk mascot.

Jan 31: Michael Sanders shows how to quickly build an AWK GUI for windows.

Jan 31: Hyung-Hwan Chung offers QSE, an embeddable Awk Interpreter.

[More ...]

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categories: Tips,Apr,2009,ArnoldR

Moving Files with Awk

Andrew Eaton wrote at comp.lang.awk:

I just started with awk and sed, I am more of a perl/C/C++ person. I have a quick question reguarding the pipe. In Awk, I am trying to use this construct.

while ((getline < "somedata.txt") > 0)
            {print | "mv"} #or could be "mv -v" for verbose. 

Is it possible that "print" is no longer printing the value of getline, if so how do I correct it?

Arnold Robbins comments:

The problem here is that `mv' doesn't read standard input, it only processes command lines. Assuming that your data is something like:

oldfile newfile

You can do things two ways:

# build the command and execute it
while ((getline < "somedata.txt") > 0) {
          command = "mv " $1 " " $2
          system(command)
}
close("somedata.txt")

or this way:

# send commands to the shell
while ((getline < "somedata.txt") > 0) {
          printf("mv %s %s\n", $1, $2) | "sh"
}
close("somedata.txt")
close("sh")

The latter is more efficient.

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