Shell Helpers¶

Constants¶

Version of this script¶

SCRIPT_HELPER_VERSION: 1.0

Log Levels¶

DEBUG: 0
D: 0
INFO: 1
I: 1
WARN: 2
W: 2
ERROR: 3
E: 3

Functions¶

command_present¶

Check if a command (or alias/function) is available.

Usage: command_present bin

bin: name of command
for cmd in 'grep' 'xterm'; do
    command_present "$cmd" || die "$cmd not found"
done

detect_all¶

Run all detection routines.

Usage: detect_all

Returns: true if all detections succeed
detect all || die 'Detections failed'

detect_arch¶

Detect architecture of running system.

Usage: detect_arch

Returns: true if detection succeeds

Exports: H_ARCH
detect_arch || die 'Architecture is not supported'

detect_codename¶

Detect codename of running system.

Usage: detect_codename

Returns: true if detection succeeds

Exports: H_CODENAME
detect_codename || die 'Distro codename not found'

detect_distro¶

Detect distribution of running system.

Usage: detect_distro

Returns: true if detection succeeds

Exports: H_DISTRO
detect_distro || die 'Distribution is not supported'

detect_init¶

Detect init of running system.

Usage: detect_init

Returns: true if detection succeeds

Exports: H_INIT
detect_init || die 'Distro is not supported'

detect_kernel¶

Detect kernel of running system.

Usage: detect_kernel

Returns: true if detection succeeds

Exports: H_KERNEL
detect_kernel || die 'Kernel is not supported'

detect_release¶

Detect distro release of running system.

Usage: detect_release

Returns: true if detection succeeds

Exports: H_RELEASE
detect_release || die 'Release is not supported'

detect_virtual¶

Attempts to detect virtualization platform of running system

Usage: detect_virtual

Exports: H_VIRTUAL (H_VIRTUAL=’’ if no platform detected)
detect_virtual

die¶

Print a formatted (critical) message and exit with status.

Usage: die [exit_status] message

exit_status: exit code to use with script termination (default: 1)

message: message to print before terminating script execution
[ -n "$foo" ] || die 255 '$foo not defined'

ends_with¶

Check if string ends with another string

Usage: ends_with key str

key: string to search for

str: ascii string to search

Returns: true if str ends with key
ends_with 'init' "$input" || die 'invalid input'
low="$(to_lower "$up")"

helper_version¶

Return true if script version is between min/max (‘dev’ == git_HEAD).

Usage: helper_version min [max]

min: minimum supported version

max: maximum supported version

Returns: true if script version is between min and [optionally:max]
helper_version '1.0.0' '1.999' ||
    die 'Helper version 1.x required!'

in_string¶

Check if a value is present in a string.

Usage: in_string needle haystack

needle: value to search for

haystack: string to be searched

Returns: true if needle was found
in_string 'fuz' 'abcfuz123' && echo 'found some fuz'

internet_reachable¶

A best-effort attempt to check if the internet is accepssible.

Usage: internet_accessible

Defaults:

env[PING_HOST]: google.com

env[PING_ADDR]: 8.8.8.8

Returns: true if internet was probed
internet_accessible || die 'Cannot reach the internet'

is_arch¶

Evaluate if running arch matches provided argument(s).

Usage: is_arch match [match..]

match: any string to test against (debian, ubuntu, etc.)

Returns: true if running arch matches a provided ‘match’
is_arch 'i386' 'x86_64' || die 'Architecture not supported'

is_codename¶

Evaluate if running codename matches provided argument(s).

Usage: is_codename match [match..]

match: any string to test against (buster, catalina, etc.)

Returns: true if running codename matches a provided ‘match’
is_codename 'buster' || die 'Only Debian buster is supported'

is_distro¶

Evaluate if running distribution matches provided argument(s).

Usage: is_distro match [match..]

match: any string to test against (debian, ubuntu, etc.)

Returns: true if running distro matches a provided ‘match’
is_distro 'debian' || die 'Only Debian is supported'

is_false¶

Evaluate if a given string is not true-like.

Usage: is_false str

str: any string to test against

Returns: true if ($str != 0) or (lower($str) != true)
is_false 'lies' || die 'I am too gullible'

is_init¶

Evaluate if running init matches provided argument(s).

Usage: is_init match [match..]

match: any string to test against (sysv, systemd, etc.)

Returns: true if running init matches a provided ‘match’
is_init 'sysv' || die 'Only sysv is supported'

is_int¶

Evaluate if a given string is a int.

Usage: is_int str

str: any string to test against

Returns: true if str is an integer
is_int "$foo" || die 'Argument must be an integer.'

is_kernel¶

Evaluate if running kernel matches provided argument(s).

Usage: is_kernel match [match..]

match: any string to test against (Linux, BSD, etc.)

Returns: true if running kernel matches a provided ‘match’
is_kernel 'Linux' 'BSD' || die 'Only Linux/BSD are supported'

is_release¶

Evaluate if running distro release matches provided argument.

Usage: is_release match [match..]

match: any string to test against (12.04, 10.1, etc.)

Returns: true if running release matches a provided ‘match’
is_release '14.04' '16.04' '18.04' '20.04' ||
    die 'Only non-EOL LTS releases are supported'

is_true¶

Evaluate if a given string is true-like.

Usage: is_true str

str: any string to test against

Returns: true if ($str is 0) or (lower($str) == true)
is_true "$foo" || die "\$foo said it isn't so..."

is_virtual¶

Evaluate if the current system is running on a virtualization platform.

Usage: is_virt [type..]

type: if provided, check if virt platform matches at least one type

Returns: true if virtual OR if H_VIRT==type
is_virtual && die 'Must be run on physical hardware'
is_virtual 'kvm' || die 'Only KVM is supported'

lock¶

Manage a lock file.

Usage: lock operation [key]

operation: acquire, destroy

key: any unique value to identify this script (default: $0)

Returns: true if success
lock aquire "$0" || die 'Unable to grab lock.'
[...]
lock destroy "$0"

log¶

Print a formatted message if env[LOG_LEVEL] >= level.

Usage: log level message

level: 0:debug, 1:info, *2:warn, 3:error

message: any string of text to be sent to stdout

Defaults:

env[LOG_LEVEL]: 2
log "$INFO" 'Capturing quantum stabilizer'
capture_qs || die 'Capture failed!'

replace_substring¶

Find/replace substrings in a string.

Usage: replace_substring input find repl

input: full string to be manipulated

find: key to search for

repl: what to replace “key” with

Prints: modified string
log "$E" "$(replace_substring "$err" "$secret" '****')"

starts_with¶

Check if string starts with another string

Usage: starts_with key str

key: string to search for

str: ascii string to search

Returns: true if str starts with key
starts_with 'init' "$input" || die 'invalid input'
low="$(to_lower "$up")"

to_lower¶

Convert string from [:upper:] to [:lower:].

Usage: to_lower

str: any ascii string to convert

Prints: string in lower
low="$(to_lower "$up")"

to_upper¶

Convert string from [:lower:] to [:upper:].

Usage: to_upper

str: any ascii string to convert

Prints: string in uppercase
up="$(to_upper "$low")"

version_compare¶

Compare two versions.

Usage: version_compare version1 operator version2

operator:

-lt, <, lesser_than

-le, <=, lesser_than_or_equal

-gt, >, greater_than

-ge, >=, greater_than_or_equal

-eq, ==, equal

-ne, !=, not_equal

version{1,2}: arbitrary version strings to compare

Version Format: [0-9]+($VERSION_SEPARATOR[0-9]+)* (i.e. 90, 1.2.3.4)

Returns: true if comparison statement is correct
version_compare "$_version" '-lt' '1.0' ||
    die 'Unexpected (pre-release) version found'

Shell Helpers¶

Constants¶

Version of this script¶

Log Levels¶

Functions¶

command_present¶

detect_all¶

detect_arch¶

detect_codename¶

detect_distro¶

detect_init¶

detect_kernel¶

detect_release¶

detect_virtual¶

die¶

ends_with¶

helper_version¶

in_string¶

internet_reachable¶

is_arch¶

is_codename¶

is_distro¶

is_false¶

is_init¶

is_int¶

is_kernel¶

is_release¶

is_true¶

is_virtual¶

lock¶

log¶

replace_substring¶

starts_with¶

to_lower¶

to_upper¶

version_compare¶

Script Helpers

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