Executing date utility in awk in linux bash script

Question

I am trying to format some text from a file using awk.

The requirement is to replace the 3rd field of a colon-seperated file (:) representing epoch time with a formatted string representing the human-readable time in the follow format: DD/MM/YYYY

Here is an example file:

abc:$3$wHe$JKAP1Ry.CAcEGhD0J7SGVl.AMg.0:1427135400:0:120:7:30:: rst:$6$3WWbfvblr6FF92R5/n3mLdlSkARgfRm1:1427293800:0:40:7:30:: xyz:$1$xuTkkle203F$df.ixcn/mcuFIO90lndn:1420478400:0:90:7:30:: def:$4$vid2003mDEOF$dc2.Rkdlkfdiw8/cib6:1389547200:0:120:7:30:: ab:*$5P1wHeEG$JKA2ya.ikol30.de/ldiv.230:1449771300:0:120:7:30:: xy:$1k3lc930vs.lskdie/sldiemDIIsdk193n:1429995693:0:50:7:30:: xyy:*$tkwsMt972w.Csrl5jr.23nsoijsleqJK:1429995889:0:120:7:30::

By copying and pasting a one of the values from the 3rd field into the a command using date I have been able to create the desired results:

date -d @1427135400 +"%d/%m/%Y" 23/03/2015

Here is the awk command that I am trying to execute in the script, I have been tweeking the script here and there in hopes to get it to work, but with no luck. Note that $userFound has already stored a single line from the file listed above:

 echo $userFound | awk -F':' '{ if ( $2 ~ /^\*/ ) {$2="L"} \ if ($2 ~ /^[^*]/) {$2="P"} \ cmd="date -d @"$3" +\"%d/%m/%Y\"" \ cmd | getline time \ close(cmd) \ } \ END { \ print $1":"$2":"time":"$4":"$5":"$6":"$7":"$8":"$9 \ }'

Running the current script, I get the following output:

awk: cmd. line:5: (FILENAME=- FNR=1) fatal: expression for `|' redirection has null string value

You're script doesn't have the (FILENAME=- FNR=1) part, please post the whole thing. — bkmoney
– bkmoney, Commented Jun 5, 2015 at 7:50
The script receives the input from the pipe, all the awk code is there. The post below (marked as answer) solved the issue. Thanks for the help though! — Matt
– Matt, Commented Jun 5, 2015 at 7:57
I've posted your script with a few changes and I get what I think is the correct output. — bkmoney
– bkmoney, Commented Jun 5, 2015 at 7:59
Get rid of all the backslashes from the end of lines. Half of them aren't necessary and the other half are breaking your code. — Ed Morton
– Ed Morton, Commented Jun 5, 2015 at 12:39

anishsane · Accepted Answer · 2015-06-05 07:33:09Z

5

Don't use date command like you are trying to use.

Use awk function: strftime("%d/%m/%Y", $3).

More info here

answered Jun 5, 2015 at 7:33

anishsane

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2 Comments

Toby Speight Over a year ago

Note specifically which awks support that extension - follow inshsane's link.

Thomas Dickey Over a year ago

gawk does this. current mawk does this as well. It is not in POSIX.

bkmoney · Accepted Answer · 2015-06-05 08:06:10Z

If you really need to use the date (because you don't have GNU awk), your script works with a few changes, namely the print statement shouldn't be in the END block.

BEGIN { FS = ":" OFS = ":" } { if ( $2 ~ /^\*/ ) {$2="L"} if ($2 ~ /^[^*]/) {$2="P"} cmd="date -d @" $3 " +\"%d/%m/%Y\"" cmd | getline time close(cmd) print $1, $2, time, $4, $5, $6, $7, $8, $9 }

If you put this script in a file called a.awk, then you can do

awk -f a.awk foo.txt

And if foo.txt looks like this:

abc:$3$wHe$JKAP1Ry.CAcEGhD0J7SGVl.AMg.0:1427135400:0:120:7:30:: rst:$6$3WWbfvblr6FF92R5/n3mLdlSkARgfRm1:1427293800:0:40:7:30:: xyz:$1$xuTkkle203F$df.ixcn/mcuFIO90lndn:1420478400:0:90:7:30:: def:$4$vid2003mDEOF$dc2.Rkdlkfdiw8/cib6:1389547200:0:120:7:30:: ab:*$5P1wHeEG$JKA2ya.ikol30.de/ldiv.230:1449771300:0:120:7:30:: xy:$1k3lc930vs.lskdie/sldiemDIIsdk193n:1429995693:0:50:7:30:: xyy:*$tkwsMt972w.Csrl5jr.23nsoijsleqJK:1429995889:0:120:7:30::

Then this is the output:

abc:P:23/03/2015:0:120:7:30:: rst:P:25/03/2015:0:40:7:30:: xyz:P:05/01/2015:0:90:7:30:: def:P:12/01/2014:0:120:7:30:: ab:P:10/12/2015:0:120:7:30:: xy:P:25/04/2015:0:50:7:30:: xyy:P:25/04/2015:0:120:7:30::

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