hpr-tools/InternetArchive/function_lib.sh

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#
# Bash Functions for sourcing in scripts.
#
# This is a copy of some of the functions for HPR project use.
#
# ${HOME}/HPR/InternetArchive/function_lib.sh
#
# Revised: 2024-06-15 18:13:28
#
#=== FUNCTION ================================================================
# NAME: abs_diff
# DESCRIPTION: Compute the difference between two numbers, returning an
# absolute value
# PARAMETERS: $1 first number
# $2 second number
# RETURNS: The absolute value as a string
#===============================================================================
function abs_diff {
local p1="${1:?Usage: abs_diff n1 n2}"
local p2="${2:?Usage: abs_diff n1 n2}"
echo $((p1 >= p2 ? p1 - p2 : p2 - p1))
}
#=== FUNCTION ================================================================
# NAME: cleanup_temp
# DESCRIPTION: Cleanup temporary files in case of a keyboard interrupt
# (SIGINT) or a termination signal (SIGTERM) and at script
# exit
# PARAMETERS: * - names of temporary files to delete
# RETURNS: Nothing
#===============================================================================
function cleanup_temp {
for tmp in "$@"; do
[ -e "$tmp" ] && rm --force "$tmp"
done
exit 0
}
#=== FUNCTION ================================================================
# NAME: _DEBUG
# DESCRIPTION: Writes one or more messages if in DEBUG mode. Each argument is
# seen as a message and is written on a separate line.
# References the global variable 'DEBUG' which is expected to be
# True if debug output is wanted.
# PARAMETERS: List of messages
# RETURNS: Nothing
#===============================================================================
_DEBUG () {
[ "$DEBUG" == 0 ] && return
for msg in "$@"; do
printf 'D> %s\n' "$msg"
done
}
#=== FUNCTION ================================================================
# NAME: yes_no
# DESCRIPTION: Read a Yes or No response from STDIN (only these values are
# accepted) and return a suitable numeric value.
# PARAMETERS: 1 - Prompt string for the read
# 2 - Default value (optional)
# RETURNS: 0 for a response of Y or YES, 1 otherwise
#===============================================================================
yes_no () {
local prompt="${1:?Usage: yes_no prompt [default]}"
local default="${2^^}"
local ans res
if [[ $prompt =~ %s ]]; then
if [[ -n $default ]]; then
default=${default:0:1}
# shellcheck disable=SC2059
# {
case "$default" in
Y) printf -v prompt "$prompt" "[Y/n]" ;;
N) printf -v prompt "$prompt" "[y/N]" ;;
*) echo "Error: ${FUNCNAME[0]} @ line ${BASH_LINENO[0]}: Default must be 'Y' or 'N'"
exit 1
;;
esac
# }
else
echo "Error: ${FUNCNAME[0]} @ line ${BASH_LINENO[0]}: Default required"
exit 1
fi
fi
#
# Loop until a valid input is received
#
while true; do
#
# Read and handle CTRL-D (EOF)
#
read -r -e -p "$prompt" ans
res="$?"
if [[ $res -ne 0 ]]; then
echo "Read aborted"
return 1
fi
[ -z "$ans" ] && ans="$default"
#
# Look for valid replies and return appropriate values. Print an error
# message otherwise and loop around for another go
#
if [[ ${ans^^} =~ ^Y(E|ES)?$ ]]; then
return 0
elif [[ ${ans^^} =~ ^NO?$ ]]; then
return 1
else
echo "Invalid reply; please use 'Y' or 'N'"
fi
done
}
#=== FUNCTION ================================================================
# NAME: make_file_list
# DESCRIPTION: Given an array of filenames select from them and make
# an array of choices in a different order if required
# PARAMETERS: 1 - input array name
# 2 - output array name
# RETURNS: True (0) if a new list was generated, false (1) otherwise
#===============================================================================
make_file_list () {
local -n inarr=${1:?Usage make_file_list input_array out_array}
local -n outarr=${2:?Usage make_file_list input_array out_array}
local i msg prompt range lines choices
#
# Print the array contents
#
lines="${#inarr[@]}"
for ((i = 0; i < lines; i++)); do
printf '%-2d %s\n' "$((i+1))" "${inarr[$i]}"
done
msg="Enter a range like '1,2' or '4-7'"
if [[ $lines -eq 1 ]]; then
prompt="1"
else
prompt="1-$lines"
msg+=" (between 1 and $lines)"
fi
#
# Choose array elements by number where order is significant
#
echo "$msg"
if read_value "Files to add to list: " range "$prompt"; then
#
# If there's a range then parse it and write the relevant elements to the
# target array, otherwise exit with an error
#
if [[ -n "$range" ]]; then
range_parse "$lines" "$range" choices 0
for i in $choices; do
outarr+=("${inarr[$((i-1))]}")
done
else
echo "No files chosen; no list created"
return 1
fi
return 0
else
return 1
fi
}
#=== FUNCTION ================================================================
# NAME: range_parse
# DESCRIPTION: Parse a collection of ranges
# PARAMETERS: - maximum limit of the range
# - entered range expression (e.g. 1-3,7,14)
# - name of variable to receive the result
# RETURNS: Writes a list of values to the nominated variable
#===============================================================================
function range_parse {
local max=${1?range_parse: arg 1 missing}
local range=${2?range:parse: arg2 missing}
local result=${3?range:parse: arg3 missing}
local tosort=${4:-1}
local selection=
#
# Turn this off. It affects how some code below behaves
#
set +o nounset
#
# Remove spaces from the range
#
range=${range// /}
#
# Check for invalid characters
#
if [[ $range =~ [^0-9,-] ]]; then
echo "Invalid range: $range"
exit
fi
#
# Slice up the sub-ranges separated by commas and turn all n-m expressions
# into the intermediate values. Trim the trailing space from the
# concatenation.
#
until [[ -z $range ]]; do
if [[ $range =~ [,] ]]; then
item=${range%%,*}
range=${range#*,}
else
item=$range
range=
fi
if [[ $item =~ [-] ]]; then
item=${item//-/ }
if [[ $item =~ ^([0-9]{1,}).([0-9]{1,})$ ]]; then
# shellcheck disable=SC2086
item=$(seq -s' ' $item)
else
echo "Invalid sequence: ${item/ /-}"
item=
fi
fi
selection+="$item "
done
selection=${selection%% }
#
# Check for out of bounds problems, sort values and and make unique
#
if [[ ${#selection} -gt 0 ]]; then
#
# Validate the resulting range
#
declare -a sel err msg
for i in $selection; do
if [[ $i -lt 1 || $i -gt $max ]]; then
err+=( $i )
else
sel+=( $i )
fi
done
#
# Report any errors
#
if [[ ${#err[*]} -gt 0 ]]; then
msg=( $(for i in ${err[*]}; do echo $i; done | sort -un) )
if [[ ${#msg[*]} -gt 1 ]]; then
printf "Values out of range: %s .. %s\n" ${msg[0]} ${msg[${#msg[*]}-1]}
else
printf "Value out of range: %s\n" ${msg[0]}
fi
fi
#
# Rebuild the selection
#
selection=
if [[ ${#sel[*]} -gt 0 ]]; then
if [[ $tosort -eq 1 ]]; then
selection="$(for i in ${sel[*]}; do echo $i; done | sort -un)"
else
selection="$(for i in ${sel[*]}; do echo $i; done)"
fi
fi
fi
#
# Return the result
#
eval $result=\"$selection\"
return
}
#=== FUNCTION ================================================================
# NAME: pad
# DESCRIPTION: Pad $text to the left with $char characters to length $length
# PARAMETERS: 1 - the text string to pad (no default)
# 2 - how long the padded string is to be (default 80)
# 3 - the character to pad with (default '-')
# RETURNS: Nothing
#===============================================================================
pad () {
local text=${1?Usage: pad text [length] [character]}
local length=${2:-80}
local char=${3:--}
local line
printf -v line "%0*d%s\n" $((length - ${#text})) 0 "$text"
char=${char:0:1}
echo "${line//0/$char}"
}
#=== FUNCTION ================================================================
# NAME: read_value
# DESCRIPTION: Read a value from STDIN and handle errors.
# PARAMETERS: 1 - Prompt string for the read
# 2 - Name of variable to receive the result
# 3 - Default value (optional)
# RETURNS: 1 on error, otherwise 0
#===============================================================================
read_value () {
local prompt="${1:?Usage: read_value prompt outputname [default]}"
local outputname="${2:?Usage: read_value prompt outputname [default]}"
local default="${3:-}"
local var
#
# Make an option for the 'read' if there's a default
#
if [[ -n $default ]]; then
default="-i '$default'"
fi
#
# Read and handle CTRL-D (EOF). Use 'eval' to deal with the argument being
# a variable
#
eval "read -r -e $default -p '$prompt' var"
res="$?"
if [[ $res -ne 0 ]]; then
echo "Read aborted"
return 1
fi
#
# Return the value in the nominated variable
#
eval "$outputname='$var'"
return 0
}
#=== FUNCTION ================================================================
# NAME: define_colours
# DESCRIPTION: Defines terminal colours
# PARAMETERS: None
# RETURNS: Nothing; justs sets the variables in the namespace
#===============================================================================
define_colours () {
#
# Colour codes
#
red=$(tput setaf 1)
export red
green=$(tput setaf 2)
export green
yellow=$(tput setaf 3)
export yellow
blue=$(tput setaf 4)
export blue
purple=$(tput setaf 5)
export purple
reset=$(tput sgr0)
export reset
return
}
#=== FUNCTION ================================================================
# NAME: undefine_colours
# DESCRIPTION: Remove all the colour codes from the colour variables
# PARAMETERS: None
# RETURNS: Nothing; justs sets the variables in the namespace
#===============================================================================
undefine_colours () {
#
# Colour codes being removed
#
for code in red green yellow blue purple reset; do
eval "$code=''"
eval "export $code"
done
return
}
#=== FUNCTION ================================================================
# NAME: coloured
# DESCRIPTION: Write a message with colour codes
# PARAMETERS: 1 - colour name
# 2 - message
# RETURNS: Nothing
#===============================================================================
coloured () {
local colour="${1:-green}"
local message="${2:-no message}"
printf '%s%s%s\n' "${!colour}" "$message" "${reset}"
}
#=== FUNCTION ================================================================
# NAME: plural
# DESCRIPTION: Adds an 's' to a word depending on the size of a number (based
# on an example from O'Reilly). Also look at ngettext for a much
# more sophisticated alternative.
# PARAMETERS: 1 - the word to pluralise
# 2 - the number used to decide
# RETURNS: Nothing
#===============================================================================
plural () {
if [[ $2 -eq 1 || $2 -eq -1 ]]; then
echo "${1}"
else
echo "${1}s"
fi
}
#=== FUNCTION ================================================================
# NAME: trimpath
# DESCRIPTION: Trim a file path to its last few components for display
# PARAMETERS: $1 - path to trim
# $2 - number of elements to retain
# RETURNS: Trimmed path
#===============================================================================
trimpath () {
local path=${1:?Usage: mpath path elements}
local elements=${2:?Usage: mpath path elements}
local -a arr1 arr2
local result
# Split the path
# oldifs="$IFS"
# IFS='/' mapfile -d'/' -t arr1 <<<"$path"
IFS='/' read -r -a arr1 <<<"$path"
# IFS="$oldifs"
if [[ ${#arr1[@]} -gt $elements ]]; then
# Put the last elements in another array
mapfile -t arr2 < <(printf '%s\n' "${arr1[@]: -$elements}")
# Return the second array interleaved with '/'
result="${arr2[*]/%//}"
result="${result//\/ /\/}"
echo "${result:0:-1}"
else
echo "$path"
fi
}
#===============================================================================
# NAME: stampfile
# DESCRIPTION: Rename a file by adding a timestamp to its name. The timestamp
# is the modification time. It is added at the end by default or
# wherever the caller places a '%s'. Note there are not enough
# error checks to deal with really weird requests :-)
# PARAMETERS: $1 - name of file to rename
# $2 - optional template string
# RETURNS: Nothing
#===============================================================================
function stampfile () {
if [[ $# = 0 || $# -gt 2 ]]; then
echo "Usage: ${FUNCNAME[0]} filename [template]"
return
fi
local fname=${1}
local tp=${2:-"${fname}_%s"}
[ -e "$fname" ] || { echo "$fname does not exist"; return; }
# shellcheck disable=SC2059
new=$(printf "$tp" "$(date -r "$fname" +%Y%m%d_%H%M%S)")
mv "$fname" "$new" || { echo "Unable to mv $fname to $new"; return; }
echo "Renamed $fname to $new"
}
#
# vim: syntax=sh:ts=8:sw=4:et:tw=78:fo=tcrqn21