awk not working when used with /bin/bash -c

Question

This correctly prints test

$ echo 'this is a test' | awk '{print $4}'
test

While using this command inside /bin/bash -c does not work

/bin/bash -c "echo 'this is a test' | awk '{print $4}'"
this is a test

How can I get awk to work correctly when using with /bin/bash -c?

Yes: `/bin/bash -c "echo 'this is a test' | awk '{print \$4}'"` — 0stone0, Apr 15 '21 at 18:32
Note: You need to escape the `$`. Ill search for a duplicate ;) — 0stone0, Apr 15 '21 at 18:32
@anubhava Phh, some sort of dyslexia? 'this' !== 'test'.... Thx for the wake up call. — 0stone0, Apr 15 '21 at 18:45
Also that dupe only talks about `bash -c` but OP is asking about `awk` as well and that dupe doesn't explain why OP is getting full line in output. — anubhava, Apr 15 '21 at 18:49

score 5 · Accepted Answer · answered Apr 15 '21 at 18:33

$4 is expended by shell since you have double quoted command string.

You can check trace output by adding -x in bash command line:

bash -xc "echo 'this is a test' | awk '{print $4}'"
+ echo 'this is a test'
+ awk '{print }'
this is a test

Since $4 expands to an empty string it effectively runs awk '{print }' and thus complete line is printed in output.

To fix this, you should be using an escaped $ to avoid this expansion:

bash -c "echo 'this is a test' | awk '{print \$4}'"
test

1 Answers1