replacing timestamp with date using sed

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When using SED to replace timestamps with human readable dates the timestamp is always replaced with the epoch date plus the value placed after"\"

I have this working with Perl example but prefer to use sed. I have tried varying escape sequences and quoting "'` etc.

sed -re "s/([0-9]{10})/$(date -d @\1)/g" mac.txt

input (one string):

834|task|3||1561834555|Ods|12015|info|Task HMI starting 837|task|3||1561834702|Nailsd|5041|info|Configured with engine 6000.8403 (/opt/NAI/LinuxShield/engine/lib/liblnxfv.so), dats 9297.0000 (/opt/NAI/LinuxShield/engine/dat), 197 extensions, 0 extra drivers

Expect date conversion but results are:

834|task|3||Wed Dec 31 19:00:01 EST 1969|Ods|12015|info|Task HMI starting 837|task|3||Wed Dec 31 19:00:01 EST 1969|Nailsd|5041|info|Configured with engine 6000.8403 (/opt/NAI/LinuxShield/engine/lib/liblnxfv.so), dats 9297.0000 (/opt/NAI/LinuxShield/engine/dat), 197 extensions, 0 extra drivers 838|task.

basically: this is what is being called:

$(date -d @\1) instead of $(date -d @\1561834555)
gnu sed shell date
1 Answers

sed never sees the $(date -d @\1) -- the shell has executed that command substitution before sed launches.

You could something like this:

sed -Ee 's/([0-9]{10})/$(date -d @\1)/g' -e 's/^/echo "/' -e 's/$/"/' mac.txt | sh

(note the single quotes, preventing the shell from doing any expansions)

However, it's much more sensible to use a language that has date facilities built-in. GNU awk:

gawk -F '|' -v OFS='|' '{
    for (i=1; i<=NF; i++)
        if ($i ~ /^[0-9]{10}$/)
            $i = strftime("%c", $i)
    print
}' mac.txt

Perl will probably be installed:

perl -MPOSIX=strftime -pe 's{\b(\d{10})\b}{ strftime("%c", localtime $1) }ge' mac.txt
# or, this is more precise as it only substitutes *fields* that consist of a timestamp
perl -MPOSIX=strftime -F'\|' -lape '$_ = join "|", map { s/^(\d{10})$/ strftime("%c", localtime $1) /ge; $_ } @F' mac.txt
user_75520
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