I'm trying to do some complex things with bash in the container using ddev exec and can't seem to get it to work. For example, ddev exec cd /var/tmp results in a big error message
Failed to execute command [cd /var/tmp]: Failed to run docker-compose [-f /Users/rfay/workspace/d8git/.ddev/docker-compose.yaml exec -T web cd /var/tmp], err='exit status 126', stdout='OCI runtime exec failed: exec failed: container_linux.go:348: starting container process caused "exec: \"cd\": executable file not found in $PATH": unknown
And trying to use "||" and "&&" or shell redirection with ">" doesn't work either.
Edit 2019-05-14: As of today's ddev release, v1.8.0, the answer below is obsolete, as ddev exec and exec hooks are executed in bash context. So ddev exec "ls | grep php" now works, ddev exec "mysql db <somefile.sql" works, as does an exec hook like exec: mysql <somefile.sql
ddev exec (and the "exec" hook in config.yaml) both execute actual comamnds, and not in the context of the shell. "cd" is not a Linux command, but rather a shell built-in. And '&&', '||', and '>' or '>>' are also shell constructs. So we have to do a bit of workaround to make them work.
But we can use bash explicitly to get these things to work:
ddev exec bash -c "cd /var/tmp && ls > /tmp/junk.txt"
To do the same thing in a post-start hook in config.yaml:
hooks:
post-start:
- exec: bash -c "cd /var/tmp && ls > /tmp/junk.txt"
Note that environment variables will not persist between exec statements, because they're in different shells, so it's best if you need to keep context to do it in one-liners.
Note also that if you want to redirect stdout/stderr you can redirect either within the container (as above) or to the host (redirecting the ddev exec output) like this:
ddev exec bash -c "cd /var/tmp && ls" >/tmp/junk.txt
It's possible that ddev exec might in the future execute commands in the context of bash to make this more transparent.