gawk: Read Terminal
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1 1.1.2 Running 'awk' Without Input Files
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1
1 You can also run 'awk' without any input files. If you type the
1 following command line:
1
1 awk 'PROGRAM'
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1 'awk' applies the PROGRAM to the "standard input", which usually means
1 whatever you type on the keyboard. This continues until you indicate
1 end-of-file by typing 'Ctrl-d'. (On non-POSIX operating systems, the
1 end-of-file character may be different.)
1
1 As an example, the following program prints a friendly piece of
1 advice (from Douglas Adams's 'The Hitchhiker's Guide to the Galaxy'), to
1 keep you from worrying about the complexities of computer programming:
1
1 $ awk 'BEGIN { print "Don\47t Panic!" }'
1 -| Don't Panic!
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1 'awk' executes statements associated with 'BEGIN' before reading any
1 input. If there are no other statements in your program, as is the case
1 here, 'awk' just stops, instead of trying to read input it doesn't know
1 how to process. The '\47' is a magic way (explained later) of getting a
1 single quote into the program, without having to engage in ugly shell
1 quoting tricks.
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1 NOTE: If you use Bash as your shell, you should execute the command
1 'set +H' before running this program interactively, to disable the
1 C shell-style command history, which treats '!' as a special
1 character. We recommend putting this command into your personal
1 startup file.
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1 This next simple 'awk' program emulates the 'cat' utility; it copies
1 whatever you type on the keyboard to its standard output (why this works
1 is explained shortly):
1
1 $ awk '{ print }'
1 Now is the time for all good men
1 -| Now is the time for all good men
1 to come to the aid of their country.
1 -| to come to the aid of their country.
1 Four score and seven years ago, ...
1 -| Four score and seven years ago, ...
1 What, me worry?
1 -| What, me worry?
1 Ctrl-d
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