如何用Shell脚本提取Docker服务前缀（Stack名称）并存入变量

Got it, let's break down how to pull that prefix (your Stack name) from the Docker service name and store it in a shell variable—super straightforward with a few common shell tools.

Method 1: Bash Parameter Expansion (No External Tools Needed) #

This is my go-to because it's fast and doesn't require spawning extra processes. Use Bash's built-in string manipulation to strip everything after the first underscore:

# Define your service name variable (replace with your actual service name)
SERVICE_NAME="UAT_postgres1.gbc38equ81vj6skoknsu83ypz"

# Extract the stack name (everything before the first underscore)
STACK_NAME="${SERVICE_NAME%%_*}"

# Verify the result
echo "Stack Name: $STACK_NAME"

The %%_* syntax means: "remove the longest match of _* starting from the end of the string"—so it cuts off everything from the first underscore onwards.

Method 2: Use cut Command #

If you prefer a more explicit field-splitting approach, cut works perfectly here by splitting the string on underscores and grabbing the first field:

SERVICE_NAME="UAT_postgres1.gbc38equ81vj6skoknsu83ypz"
STACK_NAME=$(echo "$SERVICE_NAME" | cut -d '_' -f 1)

echo "Stack Name: $STACK_NAME"

• -d '_': Sets the delimiter to an underscore
• -f 1: Tells cut to return the first field

Method 3: Use awk Command #

Another reliable option is awk, which gives you flexibility if you ever need to handle more complex patterns later:

SERVICE_NAME="UAT_postgres1.gbc38equ81vj6skoknsu83ypz"
STACK_NAME=$(echo "$SERVICE_NAME" | awk -F '_' '{print $1}')

echo "Stack Name: $STACK_NAME"

• -F '_': Sets the field separator to an underscore
• {print $1}: Prints the first field of the split string

Add Error Handling (Optional) #

If you want to make sure the service name actually has an underscore (to avoid unexpected results), add a quick check:

SERVICE_NAME="UAT_postgres1.gbc38equ81vj6skoknsu83ypz"

if [[ ! "$SERVICE_NAME" =~ "_" ]]; then
    echo "Error: Service name doesn't contain an underscore—can't extract stack name!"
    exit 1
fi

STACK_NAME="${SERVICE_NAME%%_*}"
echo "Stack Name: $STACK_NAME"

内容的提问来源于stack exchange，提问作者James Taylor