Bash script

#!/bin/bash
echo Hello World!

Bash "=~" example

$ [[ 45 =~ [0-9]+ ]] && echo "45 contains digits"
45 contains digits

$ [[ "hello" =~ [0-9]+ ]] && echo "hello doesnt contains digits"
$ [[ "hello" =~ [a-z]+ ]] && echo "hello contains alphabets"
hello contains alphabets

Source: stackoverflow.com

Linux bash scripts tutorial

$ which bash

Source: linuxconfig.org

Bash script

# The bash function below utilizes the CLI tool psql to vacuum analyze tables
# in a single schema which can be identified by either passing the name of
# the schema as the first parameter to the function
# or setting the environment variable PG_SCHEMA:
#

vacuum_analyze_schema() {
    # vacuum analyze only the tables in the specified schema

    # postgres info can be supplied by either passing it as parameters to this
    # function, setting environment variables or a combination of the two
    local pg_schema="${1:-${PG_SCHEMA}}"
    local pg_db="${2:-${PG_DB}}"
    local pg_user="${3:-${PG_USER}}"
    local pg_host="${4:-${PG_HOST}}"

    echo "Vacuuming schema \`${pg_schema}\`:"

    # extract schema table names from psql output and put them in a bash array
    local psql_tbls="\dt ${pg_schema}.*"
    local sed_str="s/${pg_schema}\s+\|\s+(\w+)\s+\|.*/\1/p"
    local table_names=$( echo "${psql_tbls}" | psql -d "${pg_db}" -U "${pg_user}" -h "${pg_host}"  | sed -nr "${sed_str}" )
    local tables_array=( $( echo "${table_names}" | tr '\n' ' ' ) )

    # loop through the table names creating and executing a vacuum
    # command for each one
    for t in "${tables_array[@]}"; do
        echo "doing table \`${t}\`..."
        psql -d "${pg_db}" -U "${pg_user}" -h "${pg_host}" \
            -c "VACUUM (ANALYZE) ${pg_schema}.${t};"
    done
}

Source: stackoverflow.com

Similar codes

0 vote118 views1 answer
Xrandr 1600x900 ubuntu
Shell/Bash
67 votes152 views6 answers
How to activate python virtual environment
Shell/Bash
2 votes135 views1 answer
Python3.8 install pip
Shell/Bash
0 vote128 views1 answer
Run mongodb on docker linux
Shell/Bash
1 vote116 views1 answer
Pip install fails with connection error ssl
Shell/Bash
0 vote130 views2 answers
Nlp sklearn download gutenberg
Shell/Bash
15 votes108 views6 answers
How to remove git commit
Shell/Bash
0 vote91 views0 answer
Shell/Bash
0 vote116 views1 answer
Network device ubuntu
Shell/Bash
0 vote115 views3 answers
Conda install gdal
Shell/Bash