Shell features you didn't know you needed (or possibly even existed) #9

Source: Dev.to

Replacing / in a Git branch name for Docker tags

When converting a Git branch name like // into a Docker image tag, the / characters must be removed or replaced because Docker tags cannot contain /.

Using tr

IMAGE_TAG=$(echo "$BRANCH" | tr '/' '-')

Using sed

IMAGE_TAG=$(echo "$BRANCH" | sed -e 's/\//-/g')

Using perl

IMAGE_TAG=$(echo "$BRANCH" | perl -pe 's/\//-/g')

Using Bash parameter expansion

IMAGE_TAG=${BRANCH//\//-}

• ${VARIABLE/from/to} replaces the first occurrence of from with to.
• ${VARIABLE//from/to} replaces all occurrences of from with to.