Command-Line Syntax
The syntax for invoking awk has two forms:
awk [options
] 'script
'var
=value file(s)
awk [options
] -fscriptfile var
=value file(s)
You can specify a script directly on the command line, or you can store a script in a scriptfile and specify it with -f. gawk allows multiple -f scripts. Variables can be assigned a value on the command line. The value can be a string or numeric constant, a shell variable ($name), or a command substitution (`cmd`), but the value is available only after the BEGIN statement is executed.
awk operates on one or more files. If none are specified (or if - is specified), awk reads from standard input.
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