How do I convert an ASCII character to its decimal (or hexadecimal) value and back?

If you have a known octal or hexadecimal value (at script-writing time), you can just use printf:

   1    # POSIX
   2    printf '\x27\047\n'

This prints two literal ' characters (27 is the hexadecimal ASCII value of the character, and 47 is the octal value) and a newline.

   1    ExpandedString=$'\x27\047\u0027\U00000027\n'
   2    echo -n "$ExpandedString"

Another approach $'...' strings are escaped before evaluation and can be embedded directly in code.

If you need to convert characters (or numeric ASCII values) that are not known in advance (i.e., in variables), you can use something a little more complicated:

   1 # POSIX
   2 # chr() - converts decimal value to its ASCII character representation
   3 # ord() - converts ASCII character to its decimal value
   4 
   5 chr() {
   6   [ ${1} -lt 256 ] || return 1
   7   printf \\$(printf '%03o' $1)
   8 }

Even better to avoid using a subshell is to pass the value inside a variable instead of the command output. faster as it avoids the subshell

   1 chr () {
   2   [ ${1} -lt 256 ] || return 1
   3   printf -v val '%03o' $1 ; printf \\$val
   4 }

If you need to quote the var (recomended), use:

   1 chr() {
   2   local val
   3   [ ${1} -lt 256 ] || return 1
   4   printf -v val '%03o' "$1"
   5   printf "%b" "\\$val"
   6 }
   7 # This one requires bash 3.1.
   8 

   1 ord() {
   2   LC_CTYPE=C printf '%d' "'$1"
   3 }
   4 
   5 # hex() - converts ASCII character to a hexadecimal value
   6 # unhex() - converts a hexadecimal value to an ASCII character
   7 
   8 hex() {
   9    LC_CTYPE=C printf '%x' "'$1"
  10 }
  11 
  12 unhex() {
  13    printf \\x"$1"
  14 }
  15 
  16 # examples:
  17 
  18 chr $(ord A)    # -> A
  19 ord $(chr 65)   # -> 65
  20 

The ord function above is quite tricky.

More complete examples (with UTF-8 support)

Note about Ext Ascii and UTF-8 encoding

   1   ###########################################################################
   2   ## ord family
   3   ###########################################################################
   4   # ord        <Return Variable Name> <Char to convert> [Optional Format String]
   5   # ord_hex    <Return Variable Name> <Char to convert>
   6   # ord_oct    <Return Variable Name> <Char to convert>
   7   # ord_utf8   <Return Variable Name> <Char to convert> [Optional Format String]
   8   # ord_eascii <Return Variable Name> <Char to convert> [Optional Format String]
   9   # ord_echo                      <Char to convert> [Optional Format String]
  10   # ord_hex_echo                  <Char to convert>
  11   # ord_oct_echo                  <Char to convert>
  12   # ord_utf8_echo                 <Char to convert> [Optional Format String]
  13   # ord_eascii_echo               <Char to convert> [Optional Format String]
  14   #
  15   # Description:
  16   # converts character using native encoding to its decimal value and stores
  17   # it in the Variable specified
  18   #
  19   #       ord
  20   #       ord_hex         output in hex
  21   #       ord_hex         output in octal
  22   #       ord_utf8        forces UTF8 decoding
  23   #       ord_eascii      forces eascii decoding
  24   #       ord_echo        prints to stdout
  25   function ord {
  26           printf -v "${1?Missing Dest Variable}" "${3:-%d}" "'${2?Missing Char}"
  27   }
  28   function ord_oct {
  29           ord "${@:1:2}" "0%c"
  30   }
  31   function ord_hex {
  32           ord "${@:1:2}" "0x%x"
  33   }
  34   function ord_utf8 {
  35           LC_CTYPE=C.UTF-8 ord "${@}"
  36   }
  37   function ord_eascii {
  38           LC_CTYPE=C ord "${@}"
  39   }
  40   function ord_echo {
  41           printf "${2:-%d}" "'${1?Missing Char}"
  42   }
  43   function ord_oct_echo {
  44           ord_echo "${1}" "0%o"
  45   }
  46   function ord_hex_echo {
  47           ord_echo "${1}" "0x%x"
  48   }
  49   function ord_utf8_echo {
  50           LC_CTYPE=C.UTF-8 ord_echo "${@}"
  51   }
  52   function ord_eascii_echo {
  53           LC_CTYPE=C ord_echo "${@}"
  54   }
  55 
  56   ###########################################################################
  57   ## chr family
  58   ###########################################################################
  59   # chr_utf8   <Return Variale Name> <Integer to convert>
  60   # chr_eascii <Return Variale Name> <Integer to convert>
  61   # chr        <Return Variale Name> <Integer to convert>
  62   # chr_oct    <Return Variale Name> <Octal number to convert>
  63   # chr_hex    <Return Variale Name> <Hex number to convert>
  64   # chr_utf8_echo                  <Integer to convert>
  65   # chr_eascii_echo                <Integer to convert>
  66   # chr_echo                       <Integer to convert>
  67   # chr_oct_echo                   <Octal number to convert>
  68   # chr_hex_echo                   <Hex number to convert>
  69   #
  70   # Description:
  71   # converts decimal value to character representation an stores
  72   # it in the Variable specified
  73   #
  74   #       chr                     Tries to guess output format
  75   #       chr_utf8                forces UTF8 encoding
  76   #       chr_eascii              forces eascii encoding
  77   #       chr_echo                prints to stdout
  78   #
  79   function chr_utf8_m {
  80     local val
  81     #
  82     # bash only supports \u \U since 4.2
  83     #
  84 
  85     # here is an example how to encode
  86     # manually
  87     # this will work since Bash 3.1 as it uses -v.
  88     #
  89     if [[ ${2:?Missing Ordinal Value} -le 0x7f ]]; then
  90       printf -v val "\\%03o" "${2}"
  91     elif [[ ${2} -le 0x7ff        ]]; then
  92       printf -v val "\\%03o\\%03o" \
  93         $((  (${2}>> 6)      |0xc0 )) \
  94         $(( ( ${2}     &0x3f)|0x80 ))
  95     elif [[ ${2} -le 0xffff       ]]; then
  96       printf -v val "\\%03o\\%03o\\%03o" \
  97         $(( ( ${2}>>12)      |0xe0 )) \
  98         $(( ((${2}>> 6)&0x3f)|0x80 )) \
  99         $(( ( ${2}     &0x3f)|0x80 ))
 100     elif [[ ${2} -le 0x1fffff     ]]; then
 101       printf -v val "\\%03o\\%03o\\%03o\\%03o"  \
 102         $(( ( ${2}>>18)      |0xf0 )) \
 103         $(( ((${2}>>12)&0x3f)|0x80 )) \
 104         $(( ((${2}>> 6)&0x3f)|0x80 )) \
 105         $(( ( ${2}     &0x3f)|0x80 ))
 106     elif [[ ${2} -le 0x3ffffff    ]]; then
 107       printf -v val "\\%03o\\%03o\\%03o\\%03o\\%03o"  \
 108         $(( ( ${2}>>24)      |0xf8 )) \
 109         $(( ((${2}>>18)&0x3f)|0x80 )) \
 110         $(( ((${2}>>12)&0x3f)|0x80 )) \
 111         $(( ((${2}>> 6)&0x3f)|0x80 )) \
 112         $(( ( ${2}     &0x3f)|0x80 ))
 113     elif [[ ${2} -le 0x7fffffff ]]; then
 114       printf -v val "\\%03o\\%03o\\%03o\\%03o\\%03o\\%03o"  \
 115         $(( ( ${2}>>30)      |0xfc )) \
 116         $(( ((${2}>>24)&0x3f)|0x80 )) \
 117         $(( ((${2}>>18)&0x3f)|0x80 )) \
 118         $(( ((${2}>>12)&0x3f)|0x80 )) \
 119         $(( ((${2}>> 6)&0x3f)|0x80 )) \
 120         $(( ( ${2}     &0x3f)|0x80 ))
 121     else
 122       printf -v "${1:?Missing Dest Variable}" ""
 123       return 1
 124     fi
 125     printf -v "${1:?Missing Dest Variable}" "${val}"
 126   }
 127   function chr_utf8 {
 128           local val
 129           [[ ${2?Missing Ordinal Value} -lt 0x80000000 ]] || return 1
 130 
 131           if [[ ${2} -lt 0x100 && ${2} -ge 0x80 ]]; then
 132 
 133                   # bash 4.2 incorrectly encodes
 134                   # \U000000ff as \xff so encode manually
 135                   printf -v val "\\%03o\%03o" $(( (${2}>>6)|0xc0 )) $(( (${2}&0x3f)|0x80 ))
 136           else
 137                   printf -v val '\\U%08x' "${2}"
 138           fi
 139           printf -v ${1?Missing Dest Variable} ${val}
 140   }
 141   function chr_eascii {
 142           local val
 143           # Make sure value less than 0x100
 144           # otherwise we end up with
 145           # \xVVNNNNN
 146           # where \xVV = char && NNNNN is a number string
 147           # so chr "0x44321" => "D321"
 148           [[ ${2?Missing Ordinal Value} -lt 0x100 ]] || return 1
 149           printf -v val '\\x%02x' "${2}"
 150           printf -v ${1?Missing Dest Variable} ${val}
 151   }
 152   function chr {
 153           if [ "${LC_CTYPE:-${LC_ALL:-}}" = "C" ]; then
 154                   chr_eascii "${@}"
 155           else
 156                   chr_utf8 "${@}"
 157           fi
 158   }
 159   function chr_dec {
 160           # strip leading 0s otherwise
 161           # interpreted as Octal
 162           chr "${1}" "${2#${2%%[!0]*}}" 
 163   }
 164   function chr_oct {
 165           chr "${1}" "0${2}"
 166   }
 167   function chr_hex {
 168           chr "${1}" "0x${2#0x}"
 169   }
 170   function chr_utf8_echo {
 171           local val
 172           [[ ${1?Missing Ordinal Value} -lt 0x80000000 ]] || return 1
 173 
 174           if [[ ${1} -lt 0x100 && ${1} -ge 0x80 ]]; then
 175 
 176                   # bash 4.2 incorrectly encodes
 177                   # \U000000ff as \xff so encode manually
 178                   printf -v val '\\%03o\\%03o' $(( (${1}>>6)|0xc0 )) $(( (${1}&0x3f)|0x80 ))
 179           else
 180                   printf -v val '\\U%08x' "${1}"
 181           fi
 182           printf "${val}"
 183   }
 184   function chr_eascii_echo {
 185           local val
 186           # Make sure value less than 0x100
 187           # otherwise we end up with
 188           # \xVVNNNNN
 189           # where \xVV = char && NNNNN is a number string
 190           # so chr "0x44321" => "D321"
 191           [[ ${1?Missing Ordinal Value} -lt 0x100 ]] || return 1
 192           printf -v val '\\x%x' "${1}"
 193           printf "${val}"
 194   }
 195   function chr_echo {
 196           if [ "${LC_CTYPE:-${LC_ALL:-}}" = "C" ]; then
 197                   chr_eascii_echo "${@}"
 198           else
 199                   chr_utf8_echo "${@}"
 200           fi
 201   }
 202   function chr_dec_echo {
 203           # strip leading 0s otherwise
 204           # interpreted as Octal
 205           chr_echo "${1#${1%%[!0]*}}" 
 206   }
 207   function chr_oct_echo {
 208           chr_echo "0${1}"
 209   }
 210   function chr_hex_echo {
 211           chr_echo "0x${1#0x}"
 212   }
 213 
 214   #
 215   # Simple Validation code
 216   #
 217   function test_echo_func {
 218     local Outcome _result
 219     _result="$( "${1}" "${2}" )"
 220     [ "${_result}" = "${3}" ] && Outcome="Pass" || Outcome="Fail"
 221     printf "# %-20s %-6s => "           "${1}" "${2}" "${_result}" "${3}"
 222     printf "[ "%16q" = "%-16q"%-5s ] "  "${_result}" "${3}" "(${3//[[:cntrl:]]/_})"
 223     printf "%s\n"                       "${Outcome}"
 224 
 225 
 226   }
 227   function test_value_func {
 228     local Outcome _result
 229     "${1}" _result "${2}"
 230     [ "${_result}" = "${3}" ] && Outcome="Pass" || Outcome="Fail"
 231     printf "# %-20s %-6s => "           "${1}" "${2}" "${_result}" "${3}"
 232     printf "[ "%16q" = "%-16q"%-5s ] "  "${_result}" "${3}" "(${3//[[:cntrl:]]/_})"
 233     printf "%s\n"                       "${Outcome}"
 234   }
 235   test_echo_func  chr_echo "$(ord_echo  "A")"  "A"
 236   test_echo_func  ord_echo "$(chr_echo "65")"  "65"
 237   test_echo_func  chr_echo "$(ord_echo  "ö")"  "ö"
 238   test_value_func chr      "$(ord_echo  "A")"  "A"
 239   test_value_func ord      "$(chr_echo "65")"  "65"
 240   test_value_func chr      "$(ord_echo  "ö")"  "ö"
 241   # chr_echo             65     => [                A = A               (A)   ] Pass
 242   # ord_echo             A      => [               65 = 65              (65)  ] Pass
 243   # chr_echo             246    => [      $'\303\266' = $'\303\266'     (ö)  ] Pass
 244   # chr                  65     => [                A = A               (A)   ] Pass
 245   # ord                  A      => [               65 = 65              (65)  ] Pass
 246   # chr                  246    => [      $'\303\266' = $'\303\266'     (ö)  ] Pass
 247   #
 248 
 249 
 250   test_echo_func  chr_echo     "65"     A
 251   test_echo_func  chr_echo     "065"    5
 252   test_echo_func  chr_dec_echo "065"    A
 253   test_echo_func  chr_oct_echo "65"     5
 254   test_echo_func  chr_hex_echo "65"     e
 255   test_value_func chr          "65"     A
 256   test_value_func chr          "065"    5
 257   test_value_func chr_dec      "065"    A
 258   test_value_func chr_oct      "65"     5
 259   test_value_func chr_hex      "65"     e
 260   # chr_echo             65     => [                A = A               (A)   ] Pass
 261   # chr_echo             065    => [                5 = 5               (5)   ] Pass
 262   # chr_dec_echo         065    => [                A = A               (A)   ] Pass
 263   # chr_oct_echo         65     => [                5 = 5               (5)   ] Pass
 264   # chr_hex_echo         65     => [                e = e               (e)   ] Pass
 265   # chr                  65     => [                A = A               (A)   ] Pass
 266   # chr                  065    => [                5 = 5               (5)   ] Pass
 267   # chr_dec              065    => [                A = A               (A)   ] Pass
 268   # chr_oct              65     => [                5 = 5               (5)   ] Pass
 269   # chr_hex              65     => [                e = e               (e)   ] Pass
 270 
 271   #test_value_func chr          0xff   $'\xff'
 272   test_value_func chr_eascii   0xff   $'\xff'
 273   test_value_func chr_utf8     0xff   $'\uff'      # Note this fails because bash encodes it incorrectly
 274   test_value_func chr_utf8     0xff   $'\303\277'
 275   test_value_func chr_utf8     0x100  $'\u100'
 276   test_value_func chr_utf8     0x1000 $'\u1000'
 277   test_value_func chr_utf8     0xffff $'\uffff'
 278   # chr_eascii           0xff   => [          $'\377' = $'\377'         (�)   ] Pass
 279   # chr_utf8             0xff   => [      $'\303\277' = $'\377'         (�)   ] Fail
 280   # chr_utf8             0xff   => [      $'\303\277' = $'\303\277'     (ÿ)  ] Pass
 281   # chr_utf8             0x100  => [      $'\304\200' = $'\304\200'     (Ā)  ] Pass
 282   # chr_utf8             0x1000 => [  $'\341\200\200' = $'\341\200\200' (က) ] Pass
 283   # chr_utf8             0xffff => [  $'\357\277\277' = $'\357\277\277' (���) ] Pass
 284   test_value_func ord_utf8     "A"           65
 285   test_value_func ord_utf8     "ä"          228
 286   test_value_func ord_utf8     $'\303\277'  255
 287   test_value_func ord_utf8     $'\u100'     256
 288 
 289 
 290 
 291   #########################################################
 292   # to help debug problems try this
 293   #########################################################
 294   printf "%q\n" $'\xff'                  # => $'\377'
 295   printf "%q\n" $'\uffff'                # => $'\357\277\277'
 296   printf "%q\n" "$(chr_utf8_echo 0x100)" # => $'\304\200'
 297   #
 298   # This can help a lot when it comes to diagnosing problems
 299   # with read and or xterm program output
 300   # I use it a lot in error case to create a human readable error message
 301   # i.e.
 302   echo "Enter type to test, Enter to continue"
 303   while read -srN1 ; do
 304     ord asciiValue "${REPLY}"
 305     case "${asciiValue}" in
 306       10) echo "Goodbye" ; break ;;
 307       20|21|22) echo "Yay expected input" ;;
 308       *) printf ':( Unexpected Input 0x%02x %q "%s"\n' "${asciiValue}" "${REPLY}" "${REPLY//[[:cntrl:]]}" ;;
 309     esac
 310   done
 311 
 312   #########################################################
 313   # More exotic approach 1
 314   #########################################################
 315   # I used to use this before I figured out the LC_CTYPE=C approach
 316   # printf "EAsciiLookup=%q" "$(for (( x=0x0; x<0x100 ; x++)); do printf '%b' $(printf '\\x%02x' "$x"); done)"
 317   EAsciiLookup=$'\001\002\003\004\005\006\a\b\t\n\v\f\r\016\017\020\021\022\023'
 318   EAsciiLookup+=$'\024\025\026\027\030\031\032\E\034\035\036\037 !"#$%&\'()*+,-'
 319   EAsciiLookup+=$'./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghi'
 320   EAsciiLookup+=$'jklmnopqrstuvwxyz{|}~\177\200\201\202\203\204\205\206\207\210'
 321   EAsciiLookup+=$'\211\212\213\214\215\216\217\220\221\222\223\224\225\226\227'
 322   EAsciiLookup+=$'\230\231\232\233\234\235\236\237\240\241\242\243\244\245\246'
 323   EAsciiLookup+=$'\247\250\251\252\253\254\255\256\257\260\261\262\263\264\265'
 324   EAsciiLookup+=$'\266\267\270\271\272\273\274\275\276\277\300\301\302\303\304'
 325   EAsciiLookup+=$'\305\306\307\310\311\312\313\314\315\316\317\320\321\322\323'
 326   EAsciiLookup+=$'\324\325\326\327\330\331\332\333\334\335\336\337\340\341\342'
 327   EAsciiLookup+=$'\343\344\345\346\347\350\351\352\353\354\355\356\357\360\361'
 328   EAsciiLookup+=$'\362\363\364\365\366\367\370\371\372\373\374\375\376\377'
 329   function ord_eascii2 {
 330     local idx="${EAsciiLookup%%${2:0:1}*}"
 331     eval ${1}'=$(( ${#idx} +1 ))'
 332   }
 333 
 334   #########################################################
 335   # More exotic approach 2
 336   #########################################################
 337   #printf "EAsciiLookup2=(\n    %s\n)" "$(for (( x=0x1; x<0x100 ; x++)); do printf '%-18s'  "$(printf '[_%q]="0x%02x"' "$(printf "%b" "$(printf '\\x%02x' "$x")")" $x )" ; [ "$(($x%6))" != "0" ] || echo -en "\n    " ; done)"
 338   typeset -A EAsciiLookup2
 339   EAsciiLookup2=(
 340     [_$'\001']="0x01" [_$'\002']="0x02" [_$'\003']="0x03" [_$'\004']="0x04"
 341     [_$'\005']="0x05" [_$'\006']="0x06" [_$'\a']="0x07"   [_$'\b']="0x08"
 342     [_$'\t']="0x09"   [_'']="0x0a"      [_$'\v']="0x0b"   [_$'\f']="0x0c"
 343     [_$'\r']="0x0d"   [_$'\016']="0x0e" [_$'\017']="0x0f" [_$'\020']="0x10"
 344     [_$'\021']="0x11" [_$'\022']="0x12" [_$'\023']="0x13" [_$'\024']="0x14"
 345     [_$'\025']="0x15" [_$'\026']="0x16" [_$'\027']="0x17" [_$'\030']="0x18"
 346     [_$'\031']="0x19" [_$'\032']="0x1a" [_$'\E']="0x1b"   [_$'\034']="0x1c"
 347     [_$'\035']="0x1d" [_$'\036']="0x1e" [_$'\037']="0x1f" [_\ ]="0x20"
 348     [_\!]="0x21"      [_\"]="0x22"      [_\#]="0x23"      [_\$]="0x24"
 349     [_%]="0x25"       [_\&]="0x26"      [_\']="0x27"      [_\(]="0x28"
 350     [_\)]="0x29"      [_\*]="0x2a"      [_+]="0x2b"       [_\,]="0x2c"
 351     [_-]="0x2d"       [_.]="0x2e"       [_/]="0x2f"       [_0]="0x30"
 352     [_1]="0x31"       [_2]="0x32"       [_3]="0x33"       [_4]="0x34"
 353     [_5]="0x35"       [_6]="0x36"       [_7]="0x37"       [_8]="0x38"
 354     [_9]="0x39"       [_:]="0x3a"       [_\;]="0x3b"      [_\<]="0x3c"
 355     [_=]="0x3d"       [_\>]="0x3e"      [_\?]="0x3f"      [_@]="0x40"
 356     [_A]="0x41"       [_B]="0x42"       [_C]="0x43"       [_D]="0x44"
 357     [_E]="0x45"       [_F]="0x46"       [_G]="0x47"       [_H]="0x48"
 358     [_I]="0x49"       [_J]="0x4a"       [_K]="0x4b"       [_L]="0x4c"
 359     [_M]="0x4d"       [_N]="0x4e"       [_O]="0x4f"       [_P]="0x50"
 360     [_Q]="0x51"       [_R]="0x52"       [_S]="0x53"       [_T]="0x54"
 361     [_U]="0x55"       [_V]="0x56"       [_W]="0x57"       [_X]="0x58"
 362     [_Y]="0x59"       [_Z]="0x5a"       [_\[]="0x5b"      #[_\\]="0x5c"
 363     #[_\]]="0x5d"
 364                       [_\^]="0x5e"      [__]="0x5f"       [_\`]="0x60"
 365     [_a]="0x61"       [_b]="0x62"       [_c]="0x63"       [_d]="0x64"
 366     [_e]="0x65"       [_f]="0x66"       [_g]="0x67"       [_h]="0x68"
 367     [_i]="0x69"       [_j]="0x6a"       [_k]="0x6b"       [_l]="0x6c"
 368     [_m]="0x6d"       [_n]="0x6e"       [_o]="0x6f"       [_p]="0x70"
 369     [_q]="0x71"       [_r]="0x72"       [_s]="0x73"       [_t]="0x74"
 370     [_u]="0x75"       [_v]="0x76"       [_w]="0x77"       [_x]="0x78"
 371     [_y]="0x79"       [_z]="0x7a"       [_\{]="0x7b"      [_\|]="0x7c"
 372     [_\}]="0x7d"      [_~]="0x7e"       [_$'\177']="0x7f" [_$'\200']="0x80"
 373     [_$'\201']="0x81" [_$'\202']="0x82" [_$'\203']="0x83" [_$'\204']="0x84"
 374     [_$'\205']="0x85" [_$'\206']="0x86" [_$'\207']="0x87" [_$'\210']="0x88"
 375     [_$'\211']="0x89" [_$'\212']="0x8a" [_$'\213']="0x8b" [_$'\214']="0x8c"
 376     [_$'\215']="0x8d" [_$'\216']="0x8e" [_$'\217']="0x8f" [_$'\220']="0x90"
 377     [_$'\221']="0x91" [_$'\222']="0x92" [_$'\223']="0x93" [_$'\224']="0x94"
 378     [_$'\225']="0x95" [_$'\226']="0x96" [_$'\227']="0x97" [_$'\230']="0x98"
 379     [_$'\231']="0x99" [_$'\232']="0x9a" [_$'\233']="0x9b" [_$'\234']="0x9c"
 380     [_$'\235']="0x9d" [_$'\236']="0x9e" [_$'\237']="0x9f" [_$'\240']="0xa0"
 381     [_$'\241']="0xa1" [_$'\242']="0xa2" [_$'\243']="0xa3" [_$'\244']="0xa4"
 382     [_$'\245']="0xa5" [_$'\246']="0xa6" [_$'\247']="0xa7" [_$'\250']="0xa8"
 383     [_$'\251']="0xa9" [_$'\252']="0xaa" [_$'\253']="0xab" [_$'\254']="0xac"
 384     [_$'\255']="0xad" [_$'\256']="0xae" [_$'\257']="0xaf" [_$'\260']="0xb0"
 385     [_$'\261']="0xb1" [_$'\262']="0xb2" [_$'\263']="0xb3" [_$'\264']="0xb4"
 386     [_$'\265']="0xb5" [_$'\266']="0xb6" [_$'\267']="0xb7" [_$'\270']="0xb8"
 387     [_$'\271']="0xb9" [_$'\272']="0xba" [_$'\273']="0xbb" [_$'\274']="0xbc"
 388     [_$'\275']="0xbd" [_$'\276']="0xbe" [_$'\277']="0xbf" [_$'\300']="0xc0"
 389     [_$'\301']="0xc1" [_$'\302']="0xc2" [_$'\303']="0xc3" [_$'\304']="0xc4"
 390     [_$'\305']="0xc5" [_$'\306']="0xc6" [_$'\307']="0xc7" [_$'\310']="0xc8"
 391     [_$'\311']="0xc9" [_$'\312']="0xca" [_$'\313']="0xcb" [_$'\314']="0xcc"
 392     [_$'\315']="0xcd" [_$'\316']="0xce" [_$'\317']="0xcf" [_$'\320']="0xd0"
 393     [_$'\321']="0xd1" [_$'\322']="0xd2" [_$'\323']="0xd3" [_$'\324']="0xd4"
 394     [_$'\325']="0xd5" [_$'\326']="0xd6" [_$'\327']="0xd7" [_$'\330']="0xd8"
 395     [_$'\331']="0xd9" [_$'\332']="0xda" [_$'\333']="0xdb" [_$'\334']="0xdc"
 396     [_$'\335']="0xdd" [_$'\336']="0xde" [_$'\337']="0xdf" [_$'\340']="0xe0"
 397     [_$'\341']="0xe1" [_$'\342']="0xe2" [_$'\343']="0xe3" [_$'\344']="0xe4"
 398     [_$'\345']="0xe5" [_$'\346']="0xe6" [_$'\347']="0xe7" [_$'\350']="0xe8"
 399     [_$'\351']="0xe9" [_$'\352']="0xea" [_$'\353']="0xeb" [_$'\354']="0xec"
 400     [_$'\355']="0xed" [_$'\356']="0xee" [_$'\357']="0xef" [_$'\360']="0xf0"
 401     [_$'\361']="0xf1" [_$'\362']="0xf2" [_$'\363']="0xf3" [_$'\364']="0xf4"
 402     [_$'\365']="0xf5" [_$'\366']="0xf6" [_$'\367']="0xf7" [_$'\370']="0xf8"
 403     [_$'\371']="0xf9" [_$'\372']="0xfa" [_$'\373']="0xfb" [_$'\374']="0xfc"
 404     [_$'\375']="0xfd" [_$'\376']="0xfe" [_$'\377']="0xff"
 405   )
 406   function ord_eascii3 {
 407         local -i val="${EAsciiLookup2["_${2:0:1}"]-}"
 408         if [ "${val}" -eq 0 ]; then
 409                 case "${2:0:1}" in
 410                         ])  val=0x5d ;;
 411                         \\) val=0x5c ;;
 412                 esac
 413         fi
 414         eval "${1}"'="${val}"'
 415   }
 416   # for fun check out the following
 417   time for (( i=0 ; i <1000; i++ )); do ord TmpVar 'a'; done
 418   #  real 0m0.065s
 419   #  user 0m0.048s
 420   #  sys  0m0.000s
 421 
 422   time for (( i=0 ; i <1000; i++ )); do ord_eascii TmpVar 'a'; done
 423   #  real 0m0.239s
 424   #  user 0m0.188s
 425   #  sys  0m0.000s
 426 
 427   time for (( i=0 ; i <1000; i++ )); do ord_utf8 TmpVar 'a'; done
 428   #  real       0m0.225s
 429   #  user       0m0.180s
 430   #  sys        0m0.000s
 431 
 432   time for (( i=0 ; i <1000; i++ )); do ord_eascii2 TmpVar 'a'; done
 433   #  real 0m1.507s
 434   #  user 0m1.056s
 435   #  sys  0m0.012s
 436 
 437   time for (( i=0 ; i <1000; i++ )); do ord_eascii3 TmpVar 'a'; done
 438   #  real 0m0.147s
 439   #  user 0m0.120s
 440   #  sys  0m0.000s
 441 
 442   time for (( i=0 ; i <1000; i++ )); do ord_echo 'a' >/dev/null ; done
 443   #  real       0m0.065s
 444   #  user       0m0.044s
 445   #  sys        0m0.016s
 446 
 447   time for (( i=0 ; i <1000; i++ )); do ord_eascii_echo 'a' >/dev/null ; done
 448   #  real       0m0.089s
 449   #  user       0m0.068s
 450   #  sys        0m0.008s
 451 
 452   time for (( i=0 ; i <1000; i++ )); do ord_utf8_echo 'a' >/dev/null ; done
 453   #  real       0m0.226s
 454   #  user       0m0.172s
 455   #  sys        0m0.012s
 456 

BashFAQ/071 (last edited 2015-03-05 04:07:28 by izabera)