‘docker exec’ is used to execute a command on running container.
For example,
For example, execute the command 'docker run ubuntu sleep 1000', it starts a container with ubuntu image and execute the sleep command.
Go to other terminal and execute the command ‘docker ps’ to see all active containers.
$docker run ubuntu echo "Hello World"
Hello World
$
$docker run ubuntu sleep 5
$
$docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e73d81bec53a ubuntu "sleep 5" 15 seconds ago Exited (0) 9 seconds ago nervous_bhaskara
12bf7981e2c5 ubuntu "echo 'Hello World'" 31 seconds ago Exited (0) 29 seconds ago competent_pascal
Now use below syntax to execute a command on running container.
docker exec {containerId/containerName} {command}
$docker exec 26d4846180b3 cat /etc/profile
# /etc/profile: system-wide .profile file for the Bourne shell (sh(1))
# and Bourne compatible shells (bash(1), ksh(1), ash(1), ...).
if [ "${PS1-}" ]; then
if [ "${BASH-}" ] && [ "$BASH" != "/bin/sh" ]; then
# The file bash.bashrc already sets the default PS1.
# PS1='\h:\w\$ '
if [ -f /etc/bash.bashrc ]; then
. /etc/bash.bashrc
fi
else
if [ "`id -u`" -eq 0 ]; then
PS1='# '
else
PS1='$ '
fi
fi
fi
if [ -d /etc/profile.d ]; then
for i in /etc/profile.d/*.sh; do
if [ -r $i ]; then
. $i
fi
done
unset i
fi
