convert_flag_3_to_2.sh

#!/bin/bash

# Specify the directory path
directory="./"

# Change to the specified directory
cd "$directory" || exit

# Define the mapping array
declare -A mapping=(
	["afg"]="af"
	["zaf"]="za"
	["ala"]="ax"
	["alb"]="al"
	["dza"]="dz"
	["deu"]="de"
	["and"]="ad"
	["ago"]="ao"
	["aia"]="ai"
	["ata"]="aq"
	["atg"]="ag"
	["sau"]="sa"
	["arg"]="ar"
	["arm"]="am"
	["abw"]="aw"
	["aus"]="au"
	["aut"]="at"
	["aze"]="az"
	["bhs"]="bs"
	["bhr"]="bh"
	["bgd"]="bd"
	["brb"]="bb"
	["blr"]="by"
	["bel"]="be"
	["blz"]="bz"
	["ben"]="bj"
	["bmu"]="bm"
	["btn"]="bt"
	["bol"]="bo"
	["bes"]="bq"
	["bih"]="ba"
	["bwa"]="bw"
	["bvt"]="bv"
	["bra"]="br"
	["brn"]="bn"
	["bgr"]="bg"
	["bfa"]="bf"
	["bdi"]="bi"
	["cym"]="ky"
	["khm"]="kh"
	["cmr"]="cm"
	["can"]="ca"
	["cpv"]="cv"
	["caf"]="cf"
	["chl"]="cl"
	["chn"]="cn"
	["cxr"]="cx"
	["cyp"]="cy"
	["cck"]="cc"
	["col"]="co"
	["com"]="km"
	["cog"]="cg"
	["cod"]="cd"
	["cok"]="ck"
	["kor"]="kr"
	["prk"]="kp"
	["cri"]="cr"
	["civ"]="ci"
	["hrv"]="hr"
	["cub"]="cu"
	["cuw"]="cw"
	["dnk"]="dk"
	["dji"]="dj"
	["dom"]="do"
	["dma"]="dm"
	["egy"]="eg"
	["slv"]="sv"
	["are"]="ae"
	["ecu"]="ec"
	["eri"]="er"
	["esp"]="es"
	["est"]="ee"
	["usa"]="us"
	["eth"]="et"
	["flk"]="fk"
	["fro"]="fo"
	["fji"]="fj"
	["fin"]="fi"
	["fra"]="fr"
	["gab"]="ga"
	["gmb"]="gm"
	["geo"]="ge"
	["sgs"]="gs"
	["gha"]="gh"
	["gib"]="gi"
	["grc"]="gr"
	["grd"]="gd"
	["grl"]="gl"
	["glp"]="gp"
	["gum"]="gu"
	["gtm"]="gt"
	["ggy"]="gg"
	["gin"]="gn"
	["gnb"]="gw"
	["gnq"]="gq"
	["guy"]="gy"
	["guf"]="gf"
	["hti"]="ht"
	["hmd"]="hm"
	["hnd"]="hn"
	["hkg"]="hk"
	["hun"]="hu"
	["imn"]="im"
	["umi"]="um"
	["vgb"]="vg"
	["vir"]="vi"
	["ind"]="in"
	["idn"]="id"
	["irn"]="ir"
	["irq"]="iq"
	["irl"]="ie"
	["isl"]="is"
	["isr"]="il"
	["ita"]="it"
	["jam"]="jm"
	["jpn"]="jp"
	["jey"]="je"
	["jor"]="jo"
	["kaz"]="kz"
	["ken"]="ke"
	["kgz"]="kg"
	["kir"]="ki"
	["kwt"]="kw"
	["lao"]="la"
	["lso"]="ls"
	["lva"]="lv"
	["lbn"]="lb"
	["lbr"]="lr"
	["lby"]="ly"
	["lie"]="li"
	["ltu"]="lt"
	["lux"]="lu"
	["mac"]="mo"
	["mkd"]="mk"
	["mdg"]="mg"
	["mys"]="my"
	["mwi"]="mw"
	["mdv"]="mv"
	["mli"]="ml"
	["mlt"]="mt"
	["mnp"]="mp"
	["mar"]="ma"
	["mhl"]="mh"
	["mtq"]="mq"
	["mus"]="mu"
	["mrt"]="mr"
	["myt"]="yt"
	["mex"]="mx"
	["fsm"]="fm"
	["mda"]="md"
	["mco"]="mc"
	["mng"]="mn"
	["mne"]="me"
	["msr"]="ms"
	["moz"]="mz"
	["mmr"]="mm"
	["nam"]="na"
	["nru"]="nr"
	["npl"]="np"
	["nic"]="ni"
	["ner"]="ne"
	["nga"]="ng"
	["niu"]="nu"
	["nfk"]="nf"
	["nor"]="no"
	["ncl"]="nc"
	["nzl"]="nz"
	["iot"]="io"
	["omn"]="om"
	["uga"]="ug"
	["uzb"]="uz"
	["pak"]="pk"
	["plw"]="pw"
	["pse"]="ps"
	["pan"]="pa"
	["png"]="pg"
	["pry"]="py"
	["nld"]="nl"
	["per"]="pe"
	["phl"]="ph"
	["pcn"]="pn"
	["pol"]="pl"
	["pyf"]="pf"
	["pri"]="pr"
	["prt"]="pt"
	["qat"]="qa"
	["reu"]="re"
	["rou"]="ro"
	["gbr"]="gb"
	["rus"]="ru"
	["rwa"]="rw"
	["esh"]="eh"
	["blm"]="bl"
	["kna"]="kn"
	["smr"]="sm"
	["maf"]="mf"
	["sxm"]="sx"
	["spm"]="pm"
	["vat"]="va"
	["vct"]="vc"
	["shn"]="sh"
	["lca"]="lc"
	["slb"]="sb"
	["wsm"]="ws"
	["asm"]="as"
	["stp"]="st"
	["sen"]="sn"
	["srb"]="rs"
	["syc"]="sc"
	["sle"]="sl"
	["sgp"]="sg"
	["svk"]="sk"
	["svn"]="si"
	["som"]="so"
	["sdn"]="sd"
	["ssd"]="ss"
	["lka"]="lk"
	["swe"]="se"
	["che"]="ch"
	["sur"]="sr"
	["sjm"]="sj"
	["swz"]="sz"
	["syr"]="sy"
	["tjk"]="tj"
	["twn"]="tw"
	["tza"]="tz"
	["tcd"]="td"
	["cze"]="cz"
	["atf"]="tf"
	["tha"]="th"
	["tls"]="tl"
	["tgo"]="tg"
	["tkl"]="tk"
	["ton"]="to"
	["tto"]="tt"
	["tun"]="tn"
	["tkm"]="tm"
	["tca"]="tc"
	["tur"]="tr"
	["tuv"]="tv"
	["ukr"]="ua"
	["ury"]="uy"
	["vut"]="vu"
	["ven"]="ve"
	["vnm"]="vn"
	["wlf"]="wf"
	["yem"]="ye"
	["zmb"]="zm"
	["zwe"]="zw"
)

# Loop through all files in the directory
for file in *; do
  # Check if the file exists and is a regular file
  if [[ -f "$file" ]]; then
    # Get the file extension
    extension="${file##*.}"

    # Get the file name without the extension
    filename="${file%.*}"

    # Check if the file name is in the mapping array
    if [[ -v mapping["$filename"] ]]; then
      # Get the new file name from the mapping array
      new_filename="${mapping["$filename"]}"

      # Rename the file with the new name and the same extension
      mv -i "$file" "$new_filename.$extension"
    fi
  fi
done