Shell script Cheat Sheets

docker_vsftpd_entrypoint.sh

#!/bin/bash

if [ -z "${LOCAL_USER_ID}" ]; then
    echo LOCAL_USER_ID is empty
    exit 1;
fi

if [ -z "${LOCAL_GROUP_ID}" ]; then
    echo LOCAL_GROUP_ID is empty
    exit 1;
fi

UID_DUPLICATED_USER=`awk -F: '{ if ($3 == LOCAL_USER_ID) print $1 }' LOCAL_USER_ID="${LOCAL_USER_ID}" /etc/passwd`
if [ -n "${UID_DUPLICATED_USER}" ]; then
    echo Deleting uid duplicated user, ${UID_DUPLICATED_USER}
    userdel ${UID_DUPLICATED_USER}
fi

echo Add ftp user, as ${LOCAL_USER_ID}:${LOCAL_GROUP_ID}\(uid:gid\)
groupadd -g ${LOCAL_GROUP_ID} -o ftp
useradd -o -u ${LOCAL_USER_ID} -g ${LOCAL_GROUP_ID} ftp

exec "$@"

docker_vsftpd_start.sh

#/bin/bash

FTP_USER=myuser
FTP_PASS=mypass
FTP_PORT=8021
# Do not use Alphabetic domain name as FTP_ADDRESS.
# Use numeric ip address.
FTP_ADDRESS="FIXME"

if [ "${FTP_ADDRESS}" = "FIXME" ]; then
    echo "Fix FTP_ADDRESS first."
    exit 1;
fi

echo -e "Example usages\n\
- ./start.sh /Users/jaeyoung/workspace/docker-vsftpd\n\
"

if [ -z "${1}" ]; then
  echo "PATH Variable is empty"
  exit 1;
fi

FTP_PATH=$1

docker run -d -v "${FTP_PATH}":/home/vsftpd/${FTP_USER} \
  -p 8020:20 -p ${FTP_PORT}:21 -p 21100-21110:21100-21110 \
  -e LOCAL_USER_ID=`id -u` -e LOCAL_GROUP_ID=`id -g` \
  -e FTP_USER=${FTP_USER} -e FTP_PASS=${FTP_PASS} \
  -e PASV_ADDRESS=${FTP_ADDRESS} -e PASV_MIN_PORT=21100 -e PASV_MAX_PORT=21110 \
  --name vsftpd --restart=always vsftpd

seqtoseq_compile_and_test_cp.sh

#!/bin/bash
# Tested Environments : Centos7


get_script_path() {
  SCRIPT=`readlink -e $0`
  echo `dirname $SCRIPT`
}

cd_into_script_path() {
  SCRIPT_PATH=`get_script_path`
  cd ${SCRIPT_PATH}
}

cd_into_script_path


source ../configs/config.sh

rm -rf ${COPY_PATH}
cp -r ${PROJ_PATH} ${COPY_PATH}

Shell_script_cheet_sheets_MTEngineDependencies_start.sh

#!/bin/bash
# Tested Environments : Centos6

start_script_on_background() {
  echo "nohup ${1} > ${2} &"
  nohup ${1} > ${2} &
}

get_script_path() {
  SCRIPT=`readlink -e $0`
  echo `dirname $SCRIPT`
}

SCRIPT_PATH=`get_script_path`
echo "SCRIPT_PATH: ${SCRIPT_PATH}"
LOGDIR="${SCRIPT_PATH}/../static"
PROCESS_NAME=express
CMD="yarn start"

echo "[DESC]: cd ${SCRIPT_PATH}/.."
cd "${SCRIPT_PATH}/.."
start_script_on_background "${CMD}" "${LOGDIR}/nohup_${PROCESS_NAME}.txt"

1. Use example description
   https://gist.github.com/kujyp/2012803263c5f69cfb45f9cc858d490d#file-docker_vsftpd_start-sh-L15-L17

2. Variables null check
   https://gist.github.com/kujyp/2012803263c5f69cfb45f9cc858d490d#file-docker_vsftpd_start-sh-L19-L22

3. Get executed script path(Remove executed path dependency)
   https://gist.github.com/kujyp/2012803263c5f69cfb45f9cc858d490d#file-mtenginedependencies_start-sh-L9-L12

4. Wrap "Get executed script path"
   https://gist.github.com/kujyp/2012803263c5f69cfb45f9cc858d490d#file-seqtoseq_compile_and_test_cp-sh-L5-L13

5. Execute on background
   https://gist.github.com/kujyp/2012803263c5f69cfb45f9cc858d490d#file-mtenginedependencies_start-sh-L4-L7

6. String check
   https://gist.github.com/kujyp/2012803263c5f69cfb45f9cc858d490d#file-docker_vsftpd_start-sh-L10

7. Variable not null check
   https://gist.github.com/kujyp/2012803263c5f69cfb45f9cc858d490d#file-docker_vsftpd_entrypoint-sh-L14-L17

• Using variable in awk statement
• https://stackoverflow.com/questions/19075671/how-do-i-use-shell-variables-in-an-awk-script

echo "input data" | awk '{print var}' var="$variable"
or
awk '{print var}' var="$variable" file

8. shell file exists
   https://www.cyberciti.biz/faq/unix-linux-test-existence-of-file-in-bash/

file="/etc/hosts"
if [ -f "$file" ]
then
    echo "$file found."
else
    echo "$file not found."
fi

if [ ! -f "/data/.htpasswd" ]; then
  echo notfound
else
  echo found
fi

9. shell string first charactor
   https://stackoverflow.com/questions/1405611/how-to-extract-the-first-two-characters-of-a-string-in-shell-scripting

long="abcdefg"
echo "${long}" | cut -c1-1

10. shell insert line
    https://stackoverflow.com/questions/6537490/insert-a-line-at-specific-line-number-with-sed-or-awk

sed -i '8i This is Line 8' FILE

11. shell delete line

grep -v "pattern" file > temp && mv temp file

12. execute shell script via curl
    searching query: curl shell script execute, execute shell script via curl, shell curl
    https://gist.github.com/jnbnyc/8bb4742ada04f1615267450d521e5025

curl -s URL | bash

13. console color
    searching query: shell color, echo color
    https://stackoverflow.com/questions/5947742/how-to-change-the-output-color-of-echo-in-linux

RED='\033[0;31m'
NC='\033[0m' # No Color
printf "I ${RED}love${NC} Stack Overflow\n"
echo -e "${RED}[ASSERTION] blarblar.${NC}"

14. append file as root
    searching query: sudo append
    https://superuser.com/questions/136646/how-to-append-to-a-file-as-sudo

echo "output" | sudo tee -a file

or

sudo bash -c "somecommand >> somefile"