3

I am learning awk to advance my skills and tried

$ atq | awk "{print $1}" 
28  Wed Oct 31 10:23:00 2018
27  Tue Oct 30 21:20:00 2018
25  Tue Oct 30 21:19:00 2018
29  Wed Oct 31 10:42:00 2018
26  Tue Oct 30 21:20:00 2018
20  Tue Oct 30 18:25:00 2018
30  Wed Oct 31 10:59:00 2018
32  Wed Oct 31 21:03:00 2018
23  Tue Oct 30 18:28:00 2018
31  Wed Oct 31 13:58:00 2018
19  Tue Oct 30 15:43:00 2018
21  Tue Oct 30 18:27:00 2018

It did not work as I expected, but it's relatively easy to work small programs together

$ atq | cut -f 1
28
27
25
29
26
20
30
32
23
31
19
21

How could I retrieve the first field using awk?

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    You need single quotes around the awk commands. Commented Oct 31, 2018 at 13:25

1 Answer 1

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8

Try the below,

atq | awk '{print $1}'

The single quotes stops the shell from expanding $1 to the shell's first positional parameter.

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  • great, could you please elaborate the reasons. Commented Oct 31, 2018 at 13:24
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    An alternative would be atq | awk "{print \$1}" - sometimes there are reasons you want the double quote, and in that case, escaping the $ is necessary. Contrived example: prefix="foo: "; atq | awk "{print $prefix, \$1}". Granted, that would normally be better accomplished using awks -v variable=... syntax, but it can still be useful sometimes... Commented Oct 31, 2018 at 14:09
  • @twalberg No, you don't generally want the shell to interpolate the awk code. To use a shell variable in an awk program, import it using -v var="$var" or export it and access it through ENVIRON["var"]. Using single quotes around awk code is always possible and always what you'd want to do. Commented Nov 6, 2018 at 10:46

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