Docker container id guard bash script-CodePudding

I build a bash script to verify if certain container exists or not. If there is no input, it complains. Does your mind helping me?

#!/bin/bash

if [[ $# -eq 0 ]] 
    then echo "Docker container ID not supplied" 
elif [[ docker images | grep -q $1 ]] 
    then echo "No such container $1" 
else 
    echo $1 
fi;

Edit:

A common output for docker images is the sample below. In case the token matches the 12 input characters and no more, the container indeed exists.

REPOSITORY                   TAG            IMAGE ID       CREATED             SIZE
sappio                       latest         091f1bf3491c   About an hour ago   556MB
postgres                     11.4           53912975086f   3 years ago         312MB
node                         7.7.2-alpine   95b4a6de40c3   5 years ago         59.2MB

The use cases for this shell script are:

input: bash has_contained_id.sh
output: Docker container ID not supplied

input: bash has_contained_id.sh 1
output: "No such container 1"

input: bash has_contained_id.sh 091f1bf3491
output: "No such container 091f1bf3491"

input: bash has_contained_id.sh 091f1bf3491c
output: "091f1bf3491c"

CodePudding user response：

Assuming OP is receiving an error like:

./testme: line 9: conditional binary operator expected
./testme: line 9: syntax error near `images'
./testme: line 9: `elif [[ docker images | grep -q $1 ]]`

Then OP may want to consider the following modification:

# replace this:

elif [[ docker images | grep -q $1 ]]

# with this:

elif docker images | grep -q "$1"

Taking into consideration OP's additional requirements to match on an exact container name, and switching the echo calls for the elif and else blocks:

if [[ $# -eq 0 ]]; then
    echo "Docker container ID not supplied" 
elif docker images | grep -qw "$1"; then
    echo "$1"    
else 
    echo "No such container $1" 
fi

CodePudding user response：

With @markp-fuso I am able to achieve the shell script below:

#!/bin/bash

if [[ $# -eq 0 ]];
    then echo "Docker container ID not supplied" 
elif docker images | grep -qw "$1"; then
    len=$(expr length "$1")
    
    if [[ "$len" -eq "12" ]]; then
        echo $1
    else 
        echo "No such container $1" 
    fi;

else
    echo "No such container $1" 
fi;