├── LICENSE ├── README.md └── lib ├── libfs.bash ├── liblog.bash └── libos.bash /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. Definitions. 8 | 9 | "License" shall mean the terms and conditions for use, reproduction, 10 | and distribution as defined by Sections 1 through 9 of this document. 11 | 12 | "Licensor" shall mean the copyright owner or entity authorized by 13 | the copyright owner that is granting the License. 14 | 15 | "Legal Entity" shall mean the union of the acting entity and all 16 | other entities that control, are controlled by, or are under common 17 | control with that entity. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright [yyyy] [name of copyright owner] 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # bash-libraries 2 | 3 | A set of useful Bash libraries 4 | 5 | ## Current libraries 6 | 7 | - [liblog.bash](https://github.com/juan131/bash-libraries/blob/master/lib/liblog.bash) 8 | - [libfs.bash](https://github.com/juan131/bash-libraries/blob/master/lib/libfs.bash) 9 | - [libos.bash](https://github.com/juan131/bash-libraries/blob/master/lib/libos.bash) 10 | 11 | ## Use 12 | 13 | Load the desired library on you Bash scripts as follows: 14 | 15 | ```bash 16 | ... 17 | . /dev/stdin <<< "$(curl -s https://raw.githubusercontent.com/juan131/bash-libraries/master/lib/liblog.bash)" 18 | ... 19 | ``` 20 | 21 | ## Bash best practices 22 | 23 | Here you can find a series of tips when developing a Bash script: 24 | 25 | - Start your scripts with the proper shebang: `#!/bin/bash`. 26 | - Start each file with a description of its contents. 27 | - Use built-in options `set -o OPTION`: 28 | - **errexit**: make your script exit when a command fails. Add `|| true` to allow a command to fail. 29 | - **nounset**: make your script exit when using undeclared variables. 30 | - **pipefail**: sets the exit code of a pipeline to that of the rightmost command to exit with a non-zero status, or to zero if all commands of the pipeline exit successfully. 31 | - **xtrace**: only for debugging. 32 | - Create a main function for scripts long enough to contain at least one other function. 33 | - Use `local` when declaring variables, unless there is reason to use `declare`. 34 | - Use `readonly` when defining "read only" constants. 35 | - Use `:-` for variables that could be undeclared. 36 | - Naming conventions: 37 | - Only use uppercase on constants or when a variable is exported to the environment. 38 | - Use underscore `_` instead of `-` to separate words. Do not use _camelCase_. 39 | - Do not start variable names with special characters or numbers. 40 | - Use `. xxx.sh` instead of `source xxx.sh`. 41 | - Use `$()` over backticks. 42 | - Use `${var}` instead of `$var` when concatenating strings. 43 | - Double quote variables, no naked `$` signs. 44 | - Use `my_func() { ... }` instead of `function my_func { ... }`. 45 | - Use `&&` and `||` for simple conditionals. 46 | - Put `then;`, `do;`, etc. on the same line. 47 | - Use `[[` instead of `[`. 48 | - Prefer absolute paths. 49 | - Avoiding temporary files. Use process substitution (`<()`) to transform commands output into sth that can be used as a filename: 50 | 51 | ~~~bash 52 | # Note that if any of the wget fails, and the diff succeed, this 53 | # statement will success regarding of built-in options! 54 | diff <(wget -O - url1) <(wget -O - url2) 55 | ~~~ 56 | 57 | - Warnings and errors should go to _STDERR_. 58 | - Use `bash -x myscript.sh` for debugging. 59 | 60 | > Note: You can use [ShellCheck](https://www.shellcheck.net) to ensure your bash syntax does not contain any warning/error. Linters will be included on repositories to ensure every commit passes a series of checks. 61 | -------------------------------------------------------------------------------- /lib/libfs.bash: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | # 3 | # Library for file system actions 4 | 5 | # Load Generic Libraries 6 | # shellcheck disable=SC1091 7 | . /dev/stdin <<< "$(curl -s https://raw.githubusercontent.com/juan131/bash-libraries/master/lib/liblog.bash)" 8 | 9 | # Functions 10 | 11 | ######################## 12 | # Ensure a file/directory is owned (user and group) but the given user 13 | # Arguments: 14 | # $1 - filepath 15 | # $2 - owner 16 | # Returns: 17 | # None 18 | ######################### 19 | owned_by() { 20 | local path="${1:?path is missing}" 21 | local owner="${2:?owner is missing}" 22 | 23 | chown "$owner":"$owner" "$path" 24 | } 25 | 26 | ######################## 27 | # Ensure a directory exists and, optionally, is owned by the given user 28 | # Arguments: 29 | # $1 - directory 30 | # $2 - owner 31 | # Returns: 32 | # None 33 | ######################### 34 | ensure_dir_exists() { 35 | local dir="${1:?directory is missing}" 36 | local owner="${2:-}" 37 | 38 | mkdir -p "${dir}" 39 | if [[ -n $owner ]]; then 40 | owned_by "$dir" "$owner" 41 | fi 42 | } 43 | 44 | ######################## 45 | # Checks whether a directory is empty or not 46 | # Arguments: 47 | # $1 - directory 48 | # Returns: 49 | # Boolean 50 | ######################### 51 | is_dir_empty() { 52 | local dir="${1:?missing directory}" 53 | 54 | if [[ ! -e "$dir" ]] || [[ -z "$(ls -A "$dir")" ]]; then 55 | true 56 | else 57 | false 58 | fi 59 | } 60 | 61 | ######################## 62 | # Configure permisions and ownership recursively 63 | # Globals: 64 | # None 65 | # Arguments: 66 | # $1 - paths (as a string). 67 | # Flags: 68 | # -f|--file-mode - mode for directories. 69 | # -d|--dir-mode - mode for files. 70 | # -u|--user - user 71 | # -g|--group - group 72 | # Returns: 73 | # None 74 | ######################### 75 | configure_permissions_ownership() { 76 | local -r paths="${1:?paths is missing}" 77 | local dir_mode="" 78 | local file_mode="" 79 | local user="" 80 | local group="" 81 | 82 | # Validate arguments 83 | shift 1 84 | while [ "$#" -gt 0 ]; do 85 | case "$1" in 86 | -f|--file-mode) 87 | shift 88 | file_mode="${1:?missing mode for files}" 89 | ;; 90 | -d|--dir-mode) 91 | shift 92 | dir_mode="${1:?missing mode for directories}" 93 | ;; 94 | -u|--user) 95 | shift 96 | user="${1:?missing user}" 97 | ;; 98 | -g|--group) 99 | shift 100 | group="${1:?missing group}" 101 | ;; 102 | *) 103 | echo "Invalid command line flag $1" >&2 104 | return 1 105 | ;; 106 | esac 107 | shift 108 | done 109 | 110 | read -r -a filepaths <<< "$paths" 111 | for p in "${filepaths[@]}"; do 112 | if [[ -e "$p" ]]; then 113 | if [[ -n $dir_mode ]]; then 114 | find -L "$p" -type d -exec chmod "$dir_mode" {} \; 115 | fi 116 | if [[ -n $file_mode ]]; then 117 | find -L "$p" -type f -exec chmod "$file_mode" {} \; 118 | fi 119 | if [[ -n $user ]] && [[ -n $group ]]; then 120 | chown -LR "$user":"$group" "$p" 121 | elif [[ -n $user ]] && [[ -z $group ]]; then 122 | chown -LR "$user" "$p" 123 | elif [[ -z $user ]] && [[ -n $group ]]; then 124 | chgrp -LR "$group" "$p" 125 | fi 126 | else 127 | error "$p does not exist" 128 | fi 129 | done 130 | } 131 | -------------------------------------------------------------------------------- /lib/liblog.bash: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | # 3 | # Logging Library 4 | 5 | # Color palette 6 | RESET='\033[0m' 7 | GREEN='\033[38;5;2m' 8 | RED='\033[38;5;1m' 9 | YELLOW='\033[38;5;3m' 10 | 11 | # Functions 12 | 13 | ######################## 14 | # Log message to stderr 15 | # Arguments: 16 | # $1 - Message to log 17 | ######################### 18 | log() { 19 | printf "%b\\n" "${*}" >&2 20 | } 21 | 22 | ######################## 23 | # Log info message 24 | # Arguments: 25 | # $1 - Message to log 26 | ######################### 27 | info() { 28 | log "${GREEN}INFO ${RESET} ==> ${*}" 29 | } 30 | 31 | ######################## 32 | # Log warning message 33 | # Arguments: 34 | # $1 - Message to log 35 | ######################### 36 | warn() { 37 | log "${YELLOW}WARN ${RESET} ==> ${*}" 38 | } 39 | 40 | ######################## 41 | # Log error message 42 | # Arguments: 43 | # $1 - Message to log 44 | ######################### 45 | error() { 46 | log "${RED}ERROR ${RESET} ==> ${*}" 47 | } 48 | -------------------------------------------------------------------------------- /lib/libos.bash: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | # 3 | # Library for operating system actions 4 | 5 | # Functions 6 | 7 | ######################## 8 | # Check if an user exists in the system 9 | # Arguments: 10 | # $1 - user 11 | # Returns: 12 | # Boolean 13 | ######################### 14 | user_exists() { 15 | local user="${1:?user is missing}" 16 | id "$user" >/dev/null 2>&1 17 | } 18 | 19 | ######################## 20 | # Check if a group exists in the system 21 | # Arguments: 22 | # $1 - group 23 | # Returns: 24 | # Boolean 25 | ######################### 26 | group_exists() { 27 | local group="${1:?group is missing}" 28 | getent group "$group" >/dev/null 2>&1 29 | } 30 | 31 | ######################## 32 | # Create a group in the system if it does not exist already 33 | # Arguments: 34 | # $1 - group 35 | # Returns: 36 | # None 37 | ######################### 38 | ensure_group_exists() { 39 | local group="${1:?group is missing}" 40 | 41 | if ! group_exists "$group"; then 42 | groupadd "$group" >/dev/null 2>&1 43 | fi 44 | } 45 | 46 | ######################## 47 | # Create an user in the system if it does not exist already 48 | # Arguments: 49 | # $1 - user 50 | # $2 - group 51 | # Returns: 52 | # None 53 | ######################### 54 | ensure_user_exists() { 55 | local user="${1:?user is missing}" 56 | local group="${2:-}" 57 | 58 | if ! user_exists "$user"; then 59 | useradd "$user" >/dev/null 2>&1 60 | if [[ -n "$group" ]]; then 61 | ensure_group_exists "$group" 62 | usermod -a -G "$group" "$user" >/dev/null 2>&1 63 | fi 64 | fi 65 | } 66 | 67 | ######################## 68 | # Check if the script is currently running as root 69 | # Arguments: 70 | # $1 - user 71 | # $2 - group 72 | # Returns: 73 | # Boolean 74 | ######################### 75 | am_i_root() { 76 | if [[ "$(id -u)" = "0" ]]; then 77 | true 78 | else 79 | false 80 | fi 81 | } 82 | 83 | ######################## 84 | # Get total memory available 85 | # Arguments: 86 | # None 87 | # Returns: 88 | # Memory in bytes 89 | ######################### 90 | get_total_memory() { 91 | echo $(($(grep MemTotal /proc/meminfo | awk '{print $2}') / 1024)) 92 | } 93 | 94 | ######################### 95 | # Redirects output to /dev/null if debug mode is disabled 96 | # Globals: 97 | # DEBUG 98 | # Arguments: 99 | # $@ - Command to execute 100 | # Returns: 101 | # None 102 | ######################### 103 | debug_execute() { 104 | if ${DEBUG:-false}; then 105 | "$@" 106 | else 107 | "$@" >/dev/null 2>&1 108 | fi 109 | } 110 | 111 | ######################## 112 | # Retries a command a given number of times 113 | # Arguments: 114 | # $1 - cmd (as a string) 115 | # $2 - max retries. Default: 12 116 | # $3 - sleep between retries (in seconds). Default: 5 117 | # Returns: 118 | # Boolean 119 | ######################### 120 | retry_while() { 121 | local -r cmd="${1:?cmd is missing}" 122 | local -r retries="${2:-12}" 123 | local -r sleep_time="${3:-5}" 124 | local return_value=1 125 | 126 | read -r -a command <<< "$cmd" 127 | for ((i = 1 ; i <= retries ; i+=1 )); do 128 | "${command[@]}" && return_value=0 && break 129 | sleep "$sleep_time" 130 | done 131 | return $return_value 132 | } 133 | --------------------------------------------------------------------------------