Awk can't execute the following command with echo [SOLVED]

Plup · 2019-05-14 21:52:52

I'm trying to run this command and put an apostrophe at the beginning:

echo test | awk '{ system("echo '"'"' " $var) }'

However

sh: -c: line 0: unexpected EOF while looking for matching `''
sh: -c: line 1: syntax error: unexpected end of file

But I wanted:

'test

For example, when i run this command:

echo test | awk '{ system("echo '"e"' " $var) }'

Results:

e test

How can i add a single quote at beggining?

Last edited by Plup (2019-05-14 23:42:11)

Trilby · 2019-05-14 22:21:57

echo test | awk '{ printf "\047"; system("echo " $var); }'

But why are you using system("echo ...") in the first place?

echo test | awk '{ printf "\047%s\n", $var; }'

Last edited by Trilby (2019-05-14 22:22:59)

Plup · 2019-05-14 22:42:51

I'm a very beginner on script, so it's hard for me to say what could be put in the place of echo and what should be batter. Echo was the closest command that came into my mind.

I traied with printf and tried again with awk, but echo was the closest successful command

Plup · 2019-05-14 22:45:04

It worked! Thank you, Trilby!

echo test | awk '{ printf "\047%s\n", $var; }'

2ManyDogs · 2019-05-14 23:04:38

Please remember to mark your thread [SOLVED] (edit the title of your first post).

Trilby · 2019-05-14 23:11:24

Also note that '$var' is really just nonsense there that only coincidentally does what you want. There is no variable 'var', but as there is no variable with that name it expands to 0 which then makes that $0 or a reference to the whole line from the stdin. It'd be much more readable (and less fragile) to just explicitly reference $0.

Plup · 2019-05-14 23:41:24

Trilby wrote:

Also note that '$var' is really just nonsense there that only coincidentally does what you want. There is no variable 'var', but as there is no variable with that name it expands to 0 which then makes that $0 or a reference to the whole line from the stdin. It'd be much more readable (and less fragile) to just explicitly reference $0.

This is true, thank you again!

Arch Linux

#1 2019-05-14 21:52:52

Awk can't execute the following command with echo [SOLVED]

#2 2019-05-14 22:21:57

Re: Awk can't execute the following command with echo [SOLVED]

#3 2019-05-14 22:42:51

Re: Awk can't execute the following command with echo [SOLVED]

#4 2019-05-14 22:45:04

Re: Awk can't execute the following command with echo [SOLVED]

#5 2019-05-14 23:04:38

Re: Awk can't execute the following command with echo [SOLVED]

#6 2019-05-14 23:11:24

Re: Awk can't execute the following command with echo [SOLVED]

#7 2019-05-14 23:41:24

Re: Awk can't execute the following command with echo [SOLVED]

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