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Many New Hobbyist Programmers and Students Write Bash Scripts. Adding Help & Option in Bash Script is Easy. Here is a Basic Guide With Examples. Advanced guide will need dedicated website or books. Previously, we have talked about bash script and simple example of such script can be bash script for counting the number of balls easily for a pyramid made of balls.
Adding Help & Option in Bash Script : Basic Theory
There is a shell tool getopt. The GNU implementation of getopt(3) (used by the command-line getopt(1) on GNU/Linux) supports parsing long options. But the BSD implementation of getopt (e.g. on Mac OS X) does not support parsing long options.
getopt and getopts are different. getopts is a built-in command to bash to process command-line options in a loop and assign each found option and value in turn to built-in variables, so that we can further process them. getopt is an external utility program and it does not actually process our options for us the way that getopts does, as well as the Perl Getopt module or the Python optparse/argparse modules do. getopt canonicalize the options that are passed in -- that, is convert them to a more standard form, so that it becomes easier for a shell script to process them.
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So for execution of commands in this way :
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./shell.sh -c abc.pl /tmp/ |
it is easier and avoiding long words like --copyfile instead of -c shown above. Now, suppose this is our script’s main content :
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#!/bin/bash # main starts echo -n "Hello! $USER, today is " date +%A # main ends |
if we save it as bash-script.sh, to execute it, we will normally do these :
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chmod +x bash-script.sh && ./bash-script.sh # or chmod +x bash-script.sh && sh bash-script.sh |
Adding Help & Option in Bash Script : Add Option
But, we want to supply the name as option, then print the date with this format of command :
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./bash-script.sh -a Abhishek |
so that, we will get this output :
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Hello! Abhishek, today is Wednesday |
Quite practical example. In this case, we need to write the script in this way (tested on OS X as working, report us if you face error) :
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#!/bin/bash # A string with command options options=$@ # An array with all the arguments arguments=($options) # Loop index index=0 for argument in $options do # Incrementing index index=`expr $index + 1` # The conditions case $argument in -a) echo "Hello! ${arguments[index]}, today is `date +%A`";; -abc) echo "Hello! ${arguments[index]}, today is $(date)" ;; esac done exit; |
very basic example.
Adding Help & Option in Bash Script : Add Help
Easiest example is :
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#!/bin/bash if [ "$1" == "-h" ] ; then echo "Usage 1: ./ `basename $0` -a <anyname>" echo "Usage 2: sh `basename $0` -a <anyname>" echo "This Help File: sh `basename $0` -h" exit 0 fi # A string with command options options=$@ # An array with all the arguments arguments=($options) # Loop index index=0 for argument in $options do # Incrementing index index=`expr $index + 1` # The conditions case $argument in -a) echo "Hello! ${arguments[index]}, today is `date +%A`";; -abc) echo "Hello! ${arguments[index]}, today is $(date)" ;; esac done exit; |
If we run :
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./bash-script.sh -h |
then we will get the help :
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Usage 1: ./ bash-script.sh -a <anyname> Usage 2: sh bash-script.sh -a <anyname> This Help File: sh bash-script.sh -h |
But it has problem. It can not show anything if only ./bash-script.sh is executed. That is why we need to re-write in this way :
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#!/bin/bash usage="$(basename "$0") -- Program to demonstrate the help to life or bash, she bang, she is Kate, she fck, she is sh. She indeed is GNU/Linux. where: -h show this help text -s set the seed value (default: 42)" seed=42 while getopts ':hs:' option; do case "$option" in h) echo "$usage" exit ;; s) seed=$OPTARG ;; :) printf "missing argument for -%s\n" "$OPTARG" >&2 echo "$usage" >&2 exit 1 ;; \?) printf "illegal option: -%s\n" "$OPTARG" >&2 echo "$usage" >&2 exit 1 ;; esac done shift $((OPTIND - 1)) |
Real life example is not going to be easy. It is difficult because in real we need to authenticate, then define path and option , set errors, on error again the help will show. It is difficult as there will be minimum 2 arguments, logical flow for failure. If we do not set the flow rightly, we will not get any output! Easiest logical flow can be studied by saving this fully working example as supload.sh and executing it. We need to run command in this way :
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/supload.sh -u <username> -k <password> <dest_dir> <src_path> |
This is designed to work on OpenStack Swift or rather OpenStack Object Storage where API based authentication is allowed. With valid parameter on HP Cloud, it will print out the HTTP error. For dry run, it will throw the help options :
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#!/bin/bash # ########### Cloud Storage Uploader ################# # # Script for upload files to cloud storage supported # Cloud Files API (such as OpenStack Swift). # License: GPL-3 # #################################################### set -o noglob usage() { cat <<EOF Usage: supload.sh [-a AUTH_URL] -u <USER> -k <KEY> [-r] [[-e PATTERN]...] [options] <dest_dir> <src_path> Options: -a AUTH_URL authentication url (default: https://region-a.geo-1.identity.hpcloudsvc.com:35357/v2.0/) -u USER user name -k KEY user password -r recursive upload -M force upload without check by md5 sum -e PATTERN exclude files by pattern (shell pattern syntax, ex. .git/*) -d NUM<m:h:d> auto delete file in storage after NUM minutes or hours or days (ex. 7d) -s NUM<K:M:G> specify the maximum transfer rate you want use to upload (ex. 1M) -m FILTER add MTIME filter. Usefull to upload only new files in large directory (find -mtime syntax, ex. -1) -z FORMAT Treat file as archive of a given type and extract it after upload. Supported formats: tar, tar.gz, tar.bz2 -c enable detect mime type for file and set content-type for uploading file (usually the storage can do it self) -q quiet mode (error output only) Params: <dest_dir> destination directory or container in storage (ex. container/dir1/), not a file name <src_path> source file or directory EOF } # Defaults AUTH_URL="https://region-a.geo-1.identity.hpcloudsvc.com:35357/v2.0/" RECURSIVEMODE="" USER="" KEY="" DEST_DIR="" SRC_PATH="" MD5CHECK="1" EXPIRE="" _ttlsec="" QUIETMODE="0" DETECT_MIMETYPE="0" MTIME="" SPEED="" EXTRACT_ARCHIVE="" declare -a EXCLUDE_LIST # Utils CURL="`which curl`" CURLOPTS="--http1.0 --insecure" FILEEX=`which file` MD5SUM=`which md5sum` if [ -z "$MD5SUM" ]; then MD5SUM=`which md5` if [ -n "$MD5SUM" ]; then MD5SUM="$MD5SUM -r" fi fi # check utils if [ -z "$CURL" ]; then echo "[!] To use this script you need to install util 'curl'" exit 1 fi if [ -z "$FILEEX" ]; then echo "[~] Util 'file' not found, detection mime type will be skipped" DETECT_MIMETYPE="0" fi if [ -z "$MD5SUM" ]; then echo "[!] To use this script you need to install util 'md5sum' or 'md5'" exit 1 fi i=0 _agrs=() for arg in "$@"; do _agrs[$i]="$arg" i=$((i + 1)) done while getopts ":ra:u:k:d:Mqe:c:m:s:z:" Option; do case $Option in r ) RECURSIVEMODE="1";; a ) AUTH_URL="$OPTARG";; u ) USER="$OPTARG";; k ) KEY="$OPTARG";; M ) MD5CHECK="0";; d ) EXPIRE="$OPTARG";; q ) QUIETMODE="1";; e ) EXCLUDE_LIST=( "${EXCLUDE_LIST[@]}" "$OPTARG" );; c ) DETECT_MIMETYPE="1";; m ) MTIME="$OPTARG";; s ) SPEED="$OPTARG";; z ) EXTRACT_ARCHIVE="$OPTARG";; * ) echo "[!] Invalid option" && usage && exit 1;; esac done shift $(($OPTIND - 1)) # Hide password key if [ -n "$SELECTEL_STORAGE_PWD" ]; then KEY="$SELECTEL_STORAGE_PWD" export -n SELECTEL_STORAGE_PWD # unset elif [ -n "$KEY" ]; then export SELECTEL_STORAGE_PWD="$KEY" # reexec and hide password key exec $0 "${_agrs[@]/$KEY/*****}" fi if [[ -z "$USER" || -z "$KEY" || -z "$1" || -z "$2" ]]; then usage exit 1 fi if [ -n "$EXTRACT_ARCHIVE" ]; then case "$EXTRACT_ARCHIVE" in "tar") ;; "tar.gz") ;; "tar.bz2") ;; *) echo "[!] Invalid format for option -z" && exit 1;; esac if [ -n "$RECURSIVEMODE" ]; then echo "[!] Option -z doen't support recursive upload (-r)" exit 1 fi DETECT_MIMETYPE="" MD5CHECK="" fi _expire_invalid() { echo "[!] Invalid value for option -d. Examples: 7d, 24h, 30m" usage exit 1 } if [ -n "$EXPIRE" ]; then _e_val="${EXPIRE:0:${#EXPIRE}-1}" _e_spec="${EXPIRE: -1}" [ -z "$_e_val" ] && _expire_invalid (("$_e_val" >= 1)) || _expire_invalid case "$_e_spec" in "d") let "_ttlsec = _e_val * 86400" ;; "h") let "_ttlsec = _e_val * 3600" ;; "m") let "_ttlsec = _e_val * 60" ;; *) _expire_invalid ;; esac fi ## helper for get abspath canonical_readlink() { local filename cd `dirname "$1"`; filename=`basename "$1"`; if [ -h "$filename" ]; then canonical_readlink `readlink "$filename"`; else echo "`pwd -P`/$filename"; fi } DEST_DIR="${1%%/}/" # ensure / in end SRC_PATH=`canonical_readlink "$2"` # remove /. and / in end SRC_PATH="${SRC_PATH%/.}" SRC_PATH="${SRC_PATH%/}" ## Print message # params: # * $1 - level: 0 - info, 1 - error, 2 - debug info # * $2 - message msg() { if [ "$1" == "0" ]; then if [ "$QUIETMODE" == "0" ]; then echo "$2" return fi return fi if [ "$1" == "1" ]; then echo "$2" return fi if [ "$1" == "2" ]; then echo "[DEBUG]:" echo "$2" echo "[^^^^^]" return fi } ## Authentication request # # params: # * $1 - auth url # * $2 - user name # * $3 - user password # # If authentication is successful the function sets environment variables: # * STOR_URL - storage url (always with / in end) # * AUTH_TOKEN - authentication token # ret_codes: # * 0 - successfully # * 1 - failed auth() { local temp_file local url local user local key local resp_status url="$1" user="$2" key="$3" temp_file=`mktemp /tmp/.supload.XXXXXX` ${CURL} ${CURLOPTS} -H "X-Auth-User: ${user}" -H "X-Auth-Key: ${key}" "${url}" -s -D "${temp_file}" 1> /dev/null resp_status=`cat "${temp_file}" | head -n1 | tr -d '\r'` resp_status="${resp_status#* }" if [ "$resp_status" == "403 Forbidden" ]; then echo "[!] Deny access, auth failed!" rm -f "${temp_file}" return 1 fi STOR_URL=`cat "${temp_file}" | tr -d '\r' | awk -F': ' 'tolower($1) ~ /^x-storage-url$/ { print $2 }'` AUTH_TOKEN=`cat "${temp_file}" | tr -d '\r' | awk -F': ' 'tolower($1) ~ /^x-auth-token$/ { print $2 }'` if [[ -z "${STOR_URL}" || -z "${AUTH_TOKEN}" ]]; then echo "[!] Auth failed" cat "${temp_file}" rm -f "${temp_file}" return 1 fi STOR_URL="${STOR_URL%%/}/" rm -f "${temp_file}" } ## Url quoting # # params: # * $1 - input string # # return: quote string url_encode() { local encodedurl encodedurl="$1"; encodedurl=` echo "$encodedurl" | hexdump -v -e '1/1 "%02x\t"' -e '1/1 "%_c\n"' | LANG=C awk ' $1 == "20" { printf("%s", "%20"); next } $1 ~ /0[adAD]/ { next } # strip newlines $2 ~ /^[a-zA-Z0-9.*()\/-]$/ { printf("%s", $2); next } # pass through what we can { printf("%%%s", $1) } # take hex value of everything else '` echo "${encodedurl}" } ## Request ETAG for file from storage # # params: # * $1 - file url # # return: etag string or nothing head_etag() { local temp_file local url local etag local resp_status temp_file=`mktemp /tmp/.supload.XXXXXX` url="$1" $CURL ${CURLOPTS} -H "X-Auth-Token: ${AUTH_TOKEN}" "${url}" -s -I -D "${temp_file}" 1> /dev/null resp_status=`cat "${temp_file}" | head -n1 | tr -d '\r'` resp_status="${resp_status#* }" if [ "$resp_status" == "403 Forbidden" ]; then rm -f "${temp_file}" echo "" return 2 fi etag=`cat "${temp_file}" | egrep -i -w -o "etag: .+" | tr -d '\r' | tr '[:upper:]' '[:lower:]' | sed 's/etag: //g'` rm -f "${temp_file}" echo "$etag" } ## Detect mime-type for local file # # params: # * $1 - path to local file # # return: mime-type string or nothing content_type() { if [[ x"$DETECT_MIMETYPE" == x"0" ]]; then echo "" return 0 fi local file file=$1 if [ -z "$FILEEX" ]; then echo "" return fi echo "`$FILEEX -b --mime "$file" | awk -F\; '{ print $1 }'`" } ## Check for container existence # # params: # * $1 - container name or path # # return: "ok" if container existence or error check_container() { local url local temp_file local cont local status cont=`url_encode "${1%%/*}"` temp_file=`mktemp /tmp/.supload.XXXXXX` url="${STOR_URL}/${cont}" $CURL ${CURLOPTS} -H "X-Auth-Token:${AUTH_TOKEN}" "${url}" -s -I -D "${temp_file}" 1> /dev/null status=`cat "${temp_file}" | grep "204 No Content"` rm -f "${temp_file}" if [ -z "$status" ]; then echo "not exist" fi echo "ok" } ## Upload file # # params: # * $1 - destination path in stotage # * $2 - local file path # ret_codes: # * 0 - successfully uploaded # * 1 - upload failed # * 2 - access denied # * 3 - source file doesn't exist # * 4 - can't calc file hash # * 5 - file already uploaded # * 6 - hash doesn't match # * 7 - invalid request # return: some info about uploaded file or error messages _upload() { local temp_file local dest local dest_url local dest_file_url local src local filehash local etag local cont_type local header_etage local header_auto_delete local header_content_type local resp_status local rc local response dest="$1" src="$2" dest_url="${STOR_URL}`url_encode "$dest"`" dest_file_url="${STOR_URL}`url_encode "$dest${src##*/}"`" # check for local file existence if [[ ! -e "$src" || -d "$src" ]]; then return 3 fi # check for file hash if [ "$MD5CHECK" == "1" ]; then # local file hash filehash=`${MD5SUM} "$src" | sed 's/ .*//g'` if [ -z "$filehash" ]; then return 5 fi # compare file hash etag=`head_etag "$dest_file_url"` rc=$? if [ $rc -eq 2 ]; then return 2 # denied get ETAG from HEAD request fi if [ "z${filehash}" == "z${etag}" ] ; then return 5 fi fi # mime-type cont_type=`content_type "$src"` if [ -n "$cont_type" ]; then header_content_type="-H Content-Type:$cont_type" fi # md5 if [ "$MD5CHECK" == "1" ]; then header_etage="-H ETag:$filehash" fi # auto delete if [[ -n "$_ttlsec" ]]; then header_auto_delete="-H X-Delete-After:$_ttlsec" fi if [[ -n "$EXTRACT_ARCHIVE" ]]; then dest_url="${dest_url}?extract-archive=${EXTRACT_ARCHIVE}" header_content_type="-Hx-detect-content-type:true" fi opts="${CURLOPTS}" if [[ -n "$SPEED" ]]; then opts="${CURLOPTS} --limit-rate ${SPEED}" fi # uploading temp_file=`mktemp /tmp/.supload.XXXXXX` $CURL ${opts} -X PUT -H "X-Auth-Token: ${AUTH_TOKEN}" $header_content_type $header_etage $header_auto_delete "$dest_url" -g -T "$src" -s -D "$temp_file" 1> /dev/null response=`cat "${temp_file}"` rm -f "${temp_file}" resp_status=`echo "$response" | head -n1 | tr -d '\r'` resp_status="${resp_status#* }" # -- successful upload if [[ "$resp_status" == "201 Created" || "$resp_status" == "200 OK" ]]; then # get hash for uploaded file (from response) etag=`echo "$response" | egrep -i -w -o "etag: .+" | tr -d '\r' | tr '[:upper:]' '[:lower:]' | sed 's/etag: //g'` if [[ -n "$EXTRACT_ARCHIVE" ]]; then echo "Archive unpacked" return fi if [ -z "$etag" ]; then echo "$response" return 1 fi if [ "$MD5CHECK" == "1" ]; then if [ "z$etag" != "z$filehash" ]; then echo "$response" return 6 fi fi echo "ETag: $etag" return fi # -- handler error responses echo "$response" if [ "$resp_status" == "403 Forbidden" ]; then return 2 fi if [ "$resp_status" == "401 Unauthorized" ]; then return 2 fi if [ "$resp_status" == "400 Bad Request" ]; then return 7 fi return 1 } ## Upload file (with attempt again if failed) # # params: # * $1 - destination path in stotage # * $2 - local file path # ret_codes: # * 0 - successfully # * 1 - fail upload() { local count local src local dst local need_reauth local out dst="$1" src="$2" need_reauth="0" count=0 while [ 1 ]; do ((++count)) if [ $count -gt 5 ]; then msg 1 "[!] Failed upload $src after $((count - 1)) attempts." return 1 fi if [ "x$need_reauth" == "x1" ]; then auth "${AUTH_URL}" "${USER}" "${KEY}" rc=$? if [ $rc -eq 0 ]; then need_reauth="0" else sleep "$count" continue fi fi msg 0 "[.] Uploading $src..." out=$(_upload "$dst" "$src") rc=$? if [ $rc -eq 0 ]; then msg 0 "[*] Uploaded OK! $out" return fi if [ $rc -eq 1 ]; then msg 1 "[!] Attempt failed, try uploading again" sleep "$count" continue fi if [ $rc -eq 2 ]; then msg 1 "[!] Access denied, try reauth and uploading again" sleep "$count" need_reauth="1" continue fi if [ $rc -eq 3 ]; then msg 1 "[!] Source file $src doesn't exist!" return 1 fi if [ $rc -eq 4 ]; then msg 1 "[!] Error with calculate file hash, skip uploading $src" return 1 fi if [ $rc -eq 5 ]; then msg 0 "[.] File already uploaded" return fi if [ $rc -eq 6 ]; then msg 1 "[!] Hash doesn't match after uploading" msg 2 "$out" sleep "$count" continue fi if [ $rc -eq 7 ]; then msg 1 "[!] Something is wrong with the upload request:" msg 2 "$out" return 1 fi msg 1 "[!] Unknown error, failed upload $src" msg 2 "$out" return 1. done } ## Main main() { local rc local exc_opts auth "${AUTH_URL}" "${USER}" "${KEY}" rc=$? if [ $rc -ne 0 ]; then exit 1 fi if [ "`check_container "${DEST_DIR}"`" != "ok" ]; then echo "[!] Container not exist" exit 1 fi ## Single file uploading if [ "z${RECURSIVEMODE}" != "z1" ]; then upload "${DEST_DIR}" "${SRC_PATH}" rc=$? exit $rc fi ## Recursive uploading if [ ! -d "${SRC_PATH}" ]; then echo "[!] ${SRC_PATH} is not dir" exit 1 fi for i in "${EXCLUDE_LIST[@]}"; do exc_opts="$exc_opts -not -wholename $SRC_PATH/$i" done opts="" if [[ -n "$MTIME" ]]; then opts="-mtime ${MTIME}" fi find "${SRC_PATH}" $opts -type f $exc_opts -print0 | while read -d $'\0' f do src=$f a="${f#$SRC_PATH}" a="${a%/*}" dest="${DEST_DIR}${a#/}" dest="${dest%%/}/" upload "$dest" "$src" done rc=$? if [ $rc -eq 0 ]; then echo "[*] All files uploaded" exit 0 fi } main |
