CODEWITHSUNDEEP
dockerstdout
Evgeny A.
Evgeny A.

Reputation: 741

docker run output appears out of order

I'll go straight to an example:

docker run --rm -i alpine /bin/sh -vs <<EOF
echo BEFORE
cat /etc/*elease
echo AFTER
EOF

Output:

echo BEFORE
cat /etc/*elease
echo AFTER
BEFORE
3.9.3
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.9.3
PRETTY_NAME="Alpine Linux v3.9"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://bugs.alpinelinux.org/"
AFTER

Note that commands itself (like echo BEFORE) printed by sh -v appear before any command output (like BEFORE).

I would expect to see

echo BEFORE
BEFORE
cat /etc/*elease
3.9.3
NAME="Alpine Linux"
ID=alpine
VERSION_ID=3.9.3
PRETTY_NAME="Alpine Linux v3.9"
HOME_URL="https://alpinelinux.org/"
BUG_REPORT_URL="https://bugs.alpinelinux.org/"
echo AFTER
AFTER

I tried using stdbuf and script as for example described here, but to no avail.

I don't think I am the only one who has this problem. So I wonder

Upvotes: 0

Views: 586

Answers (1)

Evgeny A.
Evgeny A.

Reputation: 741

I was able to solve this problem by redirecting stdout to stderr:

docker run --rm -i alpine /bin/sh -vs <<EOF
exec 1>&2
echo BEFORE
cat /etc/*elease
echo AFTER
EOF

Upvotes: 1

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