9203dc26e0
InternetArchive/function_lib.sh: new file; subset of
'~/bin/function_lib.sh' which is referred to in a number of scripts.
It contains relevant functions such as 'yes_no' and 'define_colours'.
478 lines
14 KiB
Bash
478 lines
14 KiB
Bash
#
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# Bash Functions for sourcing in scripts.
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#
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# This is a copy of some of the functions for HPR project use.
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#
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# ${HOME}/HPR/InternetArchive/function_lib.sh
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#
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# Revised: 2024-06-15 18:13:28
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#
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#=== FUNCTION ================================================================
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# NAME: abs_diff
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# DESCRIPTION: Compute the difference between two numbers, returning an
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# absolute value
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# PARAMETERS: $1 first number
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# $2 second number
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# RETURNS: The absolute value as a string
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#===============================================================================
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function abs_diff {
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local p1="${1:?Usage: abs_diff n1 n2}"
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local p2="${2:?Usage: abs_diff n1 n2}"
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echo $((p1 >= p2 ? p1 - p2 : p2 - p1))
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}
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#=== FUNCTION ================================================================
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# NAME: cleanup_temp
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# DESCRIPTION: Cleanup temporary files in case of a keyboard interrupt
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# (SIGINT) or a termination signal (SIGTERM) and at script
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# exit
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# PARAMETERS: * - names of temporary files to delete
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# RETURNS: Nothing
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#===============================================================================
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function cleanup_temp {
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for tmp in "$@"; do
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[ -e "$tmp" ] && rm --force "$tmp"
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done
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exit 0
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}
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#=== FUNCTION ================================================================
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# NAME: _DEBUG
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# DESCRIPTION: Writes one or more messages if in DEBUG mode. Each argument is
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# seen as a message and is written on a separate line.
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# References the global variable 'DEBUG' which is expected to be
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# True if debug output is wanted.
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# PARAMETERS: List of messages
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# RETURNS: Nothing
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#===============================================================================
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_DEBUG () {
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[ "$DEBUG" == 0 ] && return
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for msg in "$@"; do
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printf 'D> %s\n' "$msg"
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done
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}
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#=== FUNCTION ================================================================
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# NAME: yes_no
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# DESCRIPTION: Read a Yes or No response from STDIN (only these values are
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# accepted) and return a suitable numeric value.
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# PARAMETERS: 1 - Prompt string for the read
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# 2 - Default value (optional)
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# RETURNS: 0 for a response of Y or YES, 1 otherwise
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#===============================================================================
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yes_no () {
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local prompt="${1:?Usage: yes_no prompt [default]}"
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local default="${2^^}"
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local ans res
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if [[ $prompt =~ %s ]]; then
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if [[ -n $default ]]; then
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default=${default:0:1}
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# shellcheck disable=SC2059
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# {
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case "$default" in
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Y) printf -v prompt "$prompt" "[Y/n]" ;;
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N) printf -v prompt "$prompt" "[y/N]" ;;
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*) echo "Error: ${FUNCNAME[0]} @ line ${BASH_LINENO[0]}: Default must be 'Y' or 'N'"
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exit 1
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;;
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esac
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# }
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else
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echo "Error: ${FUNCNAME[0]} @ line ${BASH_LINENO[0]}: Default required"
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exit 1
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fi
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fi
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#
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# Loop until a valid input is received
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#
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while true; do
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#
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# Read and handle CTRL-D (EOF)
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#
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read -r -e -p "$prompt" ans
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res="$?"
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if [[ $res -ne 0 ]]; then
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echo "Read aborted"
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return 1
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fi
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[ -z "$ans" ] && ans="$default"
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#
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# Look for valid replies and return appropriate values. Print an error
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# message otherwise and loop around for another go
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#
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if [[ ${ans^^} =~ ^Y(E|ES)?$ ]]; then
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return 0
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elif [[ ${ans^^} =~ ^NO?$ ]]; then
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return 1
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else
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echo "Invalid reply; please use 'Y' or 'N'"
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fi
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done
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}
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#=== FUNCTION ================================================================
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# NAME: make_file_list
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# DESCRIPTION: Given an array of filenames select from them and make
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# an array of choices in a different order if required
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# PARAMETERS: 1 - input array name
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# 2 - output array name
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# RETURNS: True (0) if a new list was generated, false (1) otherwise
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#===============================================================================
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make_file_list () {
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local -n inarr=${1:?Usage make_file_list input_array out_array}
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local -n outarr=${2:?Usage make_file_list input_array out_array}
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local i msg prompt range lines choices
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#
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# Print the array contents
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#
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lines="${#inarr[@]}"
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for ((i = 0; i < lines; i++)); do
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printf '%-2d %s\n' "$((i+1))" "${inarr[$i]}"
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done
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msg="Enter a range like '1,2' or '4-7'"
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if [[ $lines -eq 1 ]]; then
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prompt="1"
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else
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prompt="1-$lines"
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msg+=" (between 1 and $lines)"
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fi
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#
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# Choose array elements by number where order is significant
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#
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echo "$msg"
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if read_value "Files to add to list: " range "$prompt"; then
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#
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# If there's a range then parse it and write the relevant elements to the
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# target array, otherwise exit with an error
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#
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if [[ -n "$range" ]]; then
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range_parse "$lines" "$range" choices 0
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for i in $choices; do
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outarr+=("${inarr[$((i-1))]}")
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done
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else
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echo "No files chosen; no list created"
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return 1
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fi
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return 0
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else
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return 1
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fi
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}
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#=== FUNCTION ================================================================
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# NAME: range_parse
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# DESCRIPTION: Parse a collection of ranges
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# PARAMETERS: - maximum limit of the range
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# - entered range expression (e.g. 1-3,7,14)
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# - name of variable to receive the result
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# RETURNS: Writes a list of values to the nominated variable
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#===============================================================================
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function range_parse {
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local max=${1?range_parse: arg 1 missing}
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local range=${2?range:parse: arg2 missing}
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local result=${3?range:parse: arg3 missing}
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local tosort=${4:-1}
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local selection=
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#
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# Turn this off. It affects how some code below behaves
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#
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set +o nounset
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#
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# Remove spaces from the range
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#
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range=${range// /}
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#
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# Check for invalid characters
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#
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if [[ $range =~ [^0-9,-] ]]; then
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echo "Invalid range: $range"
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exit
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fi
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#
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# Slice up the sub-ranges separated by commas and turn all n-m expressions
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# into the intermediate values. Trim the trailing space from the
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# concatenation.
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#
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until [[ -z $range ]]; do
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if [[ $range =~ [,] ]]; then
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item=${range%%,*}
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range=${range#*,}
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else
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item=$range
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range=
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fi
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if [[ $item =~ [-] ]]; then
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item=${item//-/ }
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if [[ $item =~ ^([0-9]{1,}).([0-9]{1,})$ ]]; then
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# shellcheck disable=SC2086
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item=$(seq -s' ' $item)
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else
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echo "Invalid sequence: ${item/ /-}"
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item=
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fi
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fi
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selection+="$item "
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done
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selection=${selection%% }
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#
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# Check for out of bounds problems, sort values and and make unique
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#
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if [[ ${#selection} -gt 0 ]]; then
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#
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# Validate the resulting range
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#
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declare -a sel err msg
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for i in $selection; do
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if [[ $i -lt 1 || $i -gt $max ]]; then
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err+=( $i )
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else
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sel+=( $i )
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fi
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done
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#
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# Report any errors
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#
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if [[ ${#err[*]} -gt 0 ]]; then
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msg=( $(for i in ${err[*]}; do echo $i; done | sort -un) )
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if [[ ${#msg[*]} -gt 1 ]]; then
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printf "Values out of range: %s .. %s\n" ${msg[0]} ${msg[${#msg[*]}-1]}
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else
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printf "Value out of range: %s\n" ${msg[0]}
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fi
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fi
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#
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# Rebuild the selection
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#
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selection=
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if [[ ${#sel[*]} -gt 0 ]]; then
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if [[ $tosort -eq 1 ]]; then
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selection="$(for i in ${sel[*]}; do echo $i; done | sort -un)"
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else
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selection="$(for i in ${sel[*]}; do echo $i; done)"
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fi
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fi
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fi
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#
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# Return the result
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#
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eval $result=\"$selection\"
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return
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}
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#=== FUNCTION ================================================================
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# NAME: pad
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# DESCRIPTION: Pad $text to the left with $char characters to length $length
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# PARAMETERS: 1 - the text string to pad (no default)
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# 2 - how long the padded string is to be (default 80)
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# 3 - the character to pad with (default '-')
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# RETURNS: Nothing
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#===============================================================================
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pad () {
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local text=${1?Usage: pad text [length] [character]}
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local length=${2:-80}
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local char=${3:--}
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local line
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printf -v line "%0*d%s\n" $((length - ${#text})) 0 "$text"
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char=${char:0:1}
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echo "${line//0/$char}"
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}
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#=== FUNCTION ================================================================
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# NAME: read_value
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# DESCRIPTION: Read a value from STDIN and handle errors.
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# PARAMETERS: 1 - Prompt string for the read
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# 2 - Name of variable to receive the result
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# 3 - Default value (optional)
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# RETURNS: 1 on error, otherwise 0
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#===============================================================================
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read_value () {
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local prompt="${1:?Usage: read_value prompt outputname [default]}"
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local outputname="${2:?Usage: read_value prompt outputname [default]}"
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local default="${3:-}"
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local var
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#
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# Make an option for the 'read' if there's a default
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#
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if [[ -n $default ]]; then
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default="-i '$default'"
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fi
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#
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# Read and handle CTRL-D (EOF). Use 'eval' to deal with the argument being
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# a variable
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#
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eval "read -r -e $default -p '$prompt' var"
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res="$?"
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if [[ $res -ne 0 ]]; then
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echo "Read aborted"
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return 1
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fi
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#
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# Return the value in the nominated variable
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#
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eval "$outputname='$var'"
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return 0
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}
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#=== FUNCTION ================================================================
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# NAME: define_colours
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# DESCRIPTION: Defines terminal colours
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# PARAMETERS: None
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# RETURNS: Nothing; justs sets the variables in the namespace
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#===============================================================================
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define_colours () {
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#
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# Colour codes
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#
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red=$(tput setaf 1)
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export red
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green=$(tput setaf 2)
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export green
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yellow=$(tput setaf 3)
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export yellow
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blue=$(tput setaf 4)
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export blue
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purple=$(tput setaf 5)
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export purple
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reset=$(tput sgr0)
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export reset
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return
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}
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#=== FUNCTION ================================================================
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# NAME: undefine_colours
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# DESCRIPTION: Remove all the colour codes from the colour variables
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# PARAMETERS: None
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# RETURNS: Nothing; justs sets the variables in the namespace
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#===============================================================================
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undefine_colours () {
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#
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# Colour codes being removed
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#
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for code in red green yellow blue purple reset; do
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eval "$code=''"
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eval "export $code"
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done
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return
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}
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#=== FUNCTION ================================================================
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# NAME: coloured
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# DESCRIPTION: Write a message with colour codes
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# PARAMETERS: 1 - colour name
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# 2 - message
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# RETURNS: Nothing
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#===============================================================================
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coloured () {
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local colour="${1:-green}"
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local message="${2:-no message}"
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printf '%s%s%s\n' "${!colour}" "$message" "${reset}"
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}
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#=== FUNCTION ================================================================
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# NAME: plural
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# DESCRIPTION: Adds an 's' to a word depending on the size of a number (based
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# on an example from O'Reilly). Also look at ngettext for a much
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# more sophisticated alternative.
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# PARAMETERS: 1 - the word to pluralise
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# 2 - the number used to decide
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# RETURNS: Nothing
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#===============================================================================
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plural () {
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if [[ $2 -eq 1 || $2 -eq -1 ]]; then
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echo "${1}"
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else
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echo "${1}s"
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fi
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}
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#=== FUNCTION ================================================================
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# NAME: trimpath
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# DESCRIPTION: Trim a file path to its last few components for display
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# PARAMETERS: $1 - path to trim
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# $2 - number of elements to retain
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# RETURNS: Trimmed path
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#===============================================================================
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trimpath () {
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local path=${1:?Usage: mpath path elements}
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local elements=${2:?Usage: mpath path elements}
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local -a arr1 arr2
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local result
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# Split the path
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# oldifs="$IFS"
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# IFS='/' mapfile -d'/' -t arr1 <<<"$path"
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IFS='/' read -r -a arr1 <<<"$path"
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# IFS="$oldifs"
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if [[ ${#arr1[@]} -gt $elements ]]; then
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# Put the last elements in another array
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mapfile -t arr2 < <(printf '%s\n' "${arr1[@]: -$elements}")
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# Return the second array interleaved with '/'
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result="${arr2[*]/%//}"
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result="${result//\/ /\/}"
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echo "${result:0:-1}"
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else
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echo "$path"
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fi
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}
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#===============================================================================
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# NAME: stampfile
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# DESCRIPTION: Rename a file by adding a timestamp to its name. The timestamp
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# is the modification time. It is added at the end by default or
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# wherever the caller places a '%s'. Note there are not enough
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# error checks to deal with really weird requests :-)
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# PARAMETERS: $1 - name of file to rename
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# $2 - optional template string
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# RETURNS: Nothing
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#===============================================================================
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function stampfile () {
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if [[ $# = 0 || $# -gt 2 ]]; then
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echo "Usage: ${FUNCNAME[0]} filename [template]"
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return
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fi
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local fname=${1}
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local tp=${2:-"${fname}_%s"}
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[ -e "$fname" ] || { echo "$fname does not exist"; return; }
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# shellcheck disable=SC2059
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new=$(printf "$tp" "$(date -r "$fname" +%Y%m%d_%H%M%S)")
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mv "$fname" "$new" || { echo "Unable to mv $fname to $new"; return; }
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echo "Renamed $fname to $new"
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}
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#
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# vim: syntax=sh:ts=8:sw=4:et:tw=78:fo=tcrqn21
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