"exec" with "read"


 
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# 1  
Old 10-14-2013
"exec" with "read"

Hi guys...

I have been doing binary experiments yet again and came across a superb piece of code...

I extracted a very small piece and re-wrote to suit my needs:-
Code:
#!/bin/bash --posix
# bash-hexdump

# Open the file $1 to be read with an fd 3.
exec 3<"$1"

saveIFS="$IFS"
IFS=""
char="00"
val="FF"
position=0

while read -s -u 3 -d '' -r -n 1 char
do
    # """If the leading character is a single-quote or double-quote,
    # the value shall be the numeric value in the underlying codeset
    # of the character following the single-quote or double-quote."""
    printf -v val "%02X" "'$char"
    if [ ${#val} -gt 2 ]
    then
        position=$[ ( ${#val} - 2 ) ]
        val="${val:$position:2}"
    fi
    echo -n " $val "
done

echo ""

IFS="$saveIFS"

# Finally ensure fd 3 is closed.
exec 3<&-

Results:-
Code:
Last login: Mon Oct 14 11:27:22 on ttys000
AMIGA:barrywalker~> ./bin_import.sh BinaryFile.dat
 00  01  02  03  04  05  06  07  08  09  0A  0B  0C  0D  0E  0F  10  11  12  13  14  15  16 
 17  18  19  1A  1B  1C  1D  1E  1F  20  21  22  23  24  25  26  27  28  29  2A  2B  2C  2D 
 2E  2F  30  31  32  33  34  35  36  37  38  39  3A  3B  3C  3D  3E  3F  40  41  42  43  44 
 45  46  47  48  49  4A  4B  4C  4D  4E  4F  50  51  52  53  54  55  56  57  58  59  5A  5B 
 5C  5D  5E  5F  60  61  62  63  64  65  66  67  68  69  6A  6B  6C  6D  6E  6F  70  71  72 
 73  74  75  76  77  78  79  7A  7B  7C  7D  7E  7F  80  81  82  83  84  85  86  87  88  89 
 8A  8B  8C  8D  8E  8F  90  91  92  93  94  95  96  97  98  99  9A  9B  9C  9D  9E  9F  A0 
 A1  A2  A3  A4  A5  A6  A7  A8  A9  AA  AB  AC  AD  AE  AF  B0  B1  B2  B3  B4  B5  B6  B7 
 B8  B9  BA  BB  BC  BD  BE  BF  C0  C1  C2  C3  C4  C5  C6  C7  C8  C9  CA  CB  CC  CD  CE 
 CF  D0  D1  D2  D3  D4  D5  D6  D7  D8  D9  DA  DB  DC  DD  DE  DF  E0  E1  E2  E3  E4  E5 
 E6  E7  E8  E9  EA  EB  EC  ED  EE  EF  F0  F1  F2  F3  F4  F5  F6  F7  F8  F9  FA  FB  FC 
 FD  FE  FF 
AMIGA:barrywalker~>

NOTE: Binary 0, (zero), has been accepted...

QUESTION:
I understand how "exec" is creating a file descriptor from "$1" but how does this affect "read"'s ability to accept binary 0, (zero), for manipulation by "printf"...

I have searched the web but to no avail...

Can someone please explain...

TIA...
# 2  
Old 10-14-2013
This is just a wild guess: i suppose read itself doesn't have anything to do with it. Probably the shell itself "cooks away" binary zeroes as it digests input and read only gets what was put through the shell. As the shell never gets to see the file (at least not as "input", that is, from stdin) read is served the whole story and not only parts of it.

I hope this helps.

bakunin

Moderator's Comments:
Mod Comment ahh, forgot: i move the thread over to the Experts forum. This is clearly not "Dummy" stuff but pretty advanced.
# 3  
Old 10-14-2013
The -n 1 makes read only one character instead of the line (up to a \n character).
Further the -r tells to not discard leading space characters (that only fits for line mode).
IMHO the stuff can be simplified to
Code:
#!/bin/bash --posix
# bash-hexdump

char="00"
val="FF"
position=0

while IFS="" read -r -n 1 char
do
    # """If the leading character is a single-quote or double-quote,
    # the value shall be the numeric value in the underlying codeset
    # of the character following the single-quote or double-quote."""
    printf -v val "%02X" "'$char"
    if [ ${#val} -gt 2 ]
    then
        position=$[ ( ${#val} - 2 ) ]
        val="${val:$position:2}"
    fi
    echo -n " $val "
done <"$1"

echo ""

Surprisingly seems a little different!?
This User Gave Thanks to MadeInGermany For This Post:
# 4  
Old 10-14-2013
Hi MadeInGermany...

Way cool...

So therefore I had got it all wrong it is IFS and the switches that are creating the scenario...

That now makes sense and extracting your code gives the result I want without the use of exec...

I am now gonna pinch your code and modify... ;o)

Thanks a lot...

EDIT:
I forgot...
Code:
Last login: Mon Oct 14 17:59:46 on ttys000
AMIGA:barrywalker~> ./hex_dump2.sh BinaryFile.dat
 00  01  02  03  04  05  06  07  08  09  00  0B  0C  0D  0E  0F  10  11  12  13 
 14  15  16  17  18  19  1A  1B  1C  1D  1E  1F  20  21  22  23  24  25  26  27 
 28  29  2A  2B  2C  2D  2E  2F  30  31  32  33  34  35  36  37  38  39  3A  3B 
 3C  3D  3E  3F  40  41  42  43  44  45  46  47  48  49  4A  4B  4C  4D  4E  4F 
 50  51  52  53  54  55  56  57  58  59  5A  5B  5C  5D  5E  5F  60  61  62  63 
 64  65  66  67  68  69  6A  6B  6C  6D  6E  6F  70  71  72  73  74  75  76  77 
 78  79  7A  7B  7C  7D  7E  7F  80  81  82  83  84  85  86  87  88  89  8A  8B 
 8C  8D  8E  8F  90  91  92  93  94  95  96  97  98  99  9A  9B  9C  9D  9E  9F 
 A0  A1  A2  A3  A4  A5  A6  A7  A8  A9  AA  AB  AC  AD  AE  AF  B0  B1  B2  B3 
 B4  B5  B6  B7  B8  B9  BA  BB  BC  BD  BE  BF  C0  C1  C2  C3  C4  C5  C6  C7 
 C8  C9  CA  CB  CC  CD  CE  CF  D0  D1  D2  D3  D4  D5  D6  D7  D8  D9  DA  DB 
 DC  DD  DE  DF  E0  E1  E2  E3  E4  E5  E6  E7  E8  E9  EA  EB  EC  ED  EE  EF 
 F0  F1  F2  F3  F4  F5  F6  F7  F8  F9  FA  FB  FC  FD  FE  FF 
AMIGA:barrywalker~>

# 5  
Old 10-14-2013
Quote:
Originally Posted by wisecracker
QUESTION:
I understand how "exec" is creating a file descriptor from "$1" but how does this affect "read"'s ability to accept binary 0, (zero), for manipulation by "printf"...
exec has no effect whatsoever on the handling of the nullbyte.

Quote:
Originally Posted by wisecracker
NOTE: Binary 0, (zero), has been accepted...
No, it hasn't. That code is simply the beneficiary of serendipitous default behavior. The null byte is not in the variable, but printf fills any vacuums with zeroes/nullstrings, which in this case gives the correct result.

From the BASH built-in documentation, some info about printf:
Quote:
Arguments to non-string format specifiers are treated as C language constants, except that a leading plus or minus sign is allowed, and if the leading character is a single or double quote, the value is the ASCII value of the following character.

The format is reused as necessary to consume all of the arguments. If the format requires more arguments than are supplied, the extra format specifications behave as if a zero value or null string, as appropriate, had been supplied. The return value is zero on success, non-zero on failure.
In action:
Code:
$ printf '%02X'
00
$ printf '%02X' ""
00
$ unset var
$ printf '%02X' "'$var"
00

In short, it's a lucky break (but I don't think it's an unsafe dependence).

The code that you posted will not work under all circumstances. read works with characters but in a hexdump, bytes are what matter. If the locale specifies a multibyte encoding, the results will be incorrect.

I observed such breakage on one of my machines with the following environment:
Code:
$ locale
LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_ALL=

The solution is to ensure that a single-byte encoding is in effect.

I believe the following code is a simpler, more robust improvement.
Code:
#!/bin/bash --posix
# bash-hexdump

LC_CTYPE=C

while IFS= read -srd '' -n1 char
do
    printf '%02X\n' "'$char"
done

Code:
$ ./hexdump.sh < binary.dat | paste -d ' ' - - - - - - - - - - - - - - - -
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F
20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F
60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F
70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F
80 81 82 83 84 85 86 87 88 89 8A 8B 8C 8D 8E 8F
90 91 92 93 94 95 96 97 98 99 9A 9B 9C 9D 9E 9F
A0 A1 A2 A3 A4 A5 A6 A7 A8 A9 AA AB AC AD AE AF
B0 B1 B2 B3 B4 B5 B6 B7 B8 B9 BA BB BC BD BE BF
C0 C1 C2 C3 C4 C5 C6 C7 C8 C9 CA CB CC CD CE CF
D0 D1 D2 D3 D4 D5 D6 D7 D8 D9 DA DB DC DD DE DF
E0 E1 E2 E3 E4 E5 E6 E7 E8 E9 EA EB EC ED EE EF
F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 FA FB FC FD FE FF

Without LC_CTYPE=C in the script to override my system's default of LC_CTYPE=en_US.UTF-8:
Code:
$ ./hexdump.sh < binary.dat | paste -d ' ' - - - - - - - - - - - - - - - -
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F
20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F
30 31 32 33 34 35 36 37 38 39 3A 3B 3C 3D 3E 3F
40 41 42 43 44 45 46 47 48 49 4A 4B 4C 4D 4E 4F
50 51 52 53 54 55 56 57 58 59 5A 5B 5C 5D 5E 5F
60 61 62 63 64 65 66 67 68 69 6A 6B 6C 6D 6E 6F
70 71 72 73 74 75 76 77 78 79 7A 7B 7C 7D 7E 7F
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00

The preceding result, with its string of incorrect zeroes, occurred on a Windows machine using Cygwin. In a Linux (Ubuntu) virtual machine, bytes 128-255 were also mangled, but instead of double zeroes the output consisted of 16-digit hexadecimal numbers.

Multibyte character issues are also a concern when generating the binary data with a locale-aware awk implementation (in this case, gawk):
Code:
$ seq 0 255 | awk '{printf "%c", $0}' | od -Ax -tx1
000000 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
000010 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
000020 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
000030 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
000040 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
000050 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
000060 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
000070 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f
000080 c2 80 c2 81 c2 82 c2 83 c2 84 c2 85 c2 86 c2 87
000090 c2 88 c2 89 c2 8a c2 8b c2 8c c2 8d c2 8e c2 8f
0000a0 c2 90 c2 91 c2 92 c2 93 c2 94 c2 95 c2 96 c2 97
0000b0 c2 98 c2 99 c2 9a c2 9b c2 9c c2 9d c2 9e c2 9f
0000c0 c2 a0 c2 a1 c2 a2 c2 a3 c2 a4 c2 a5 c2 a6 c2 a7
0000d0 c2 a8 c2 a9 c2 aa c2 ab c2 ac c2 ad c2 ae c2 af
0000e0 c2 b0 c2 b1 c2 b2 c2 b3 c2 b4 c2 b5 c2 b6 c2 b7
0000f0 c2 b8 c2 b9 c2 ba c2 bb c2 bc c2 bd c2 be c2 bf
000100 c3 80 c3 81 c3 82 c3 83 c3 84 c3 85 c3 86 c3 87
000110 c3 88 c3 89 c3 8a c3 8b c3 8c c3 8d c3 8e c3 8f
000120 c3 90 c3 91 c3 92 c3 93 c3 94 c3 95 c3 96 c3 97
000130 c3 98 c3 99 c3 9a c3 9b c3 9c c3 9d c3 9e c3 9f
000140 c3 a0 c3 a1 c3 a2 c3 a3 c3 a4 c3 a5 c3 a6 c3 a7
000150 c3 a8 c3 a9 c3 aa c3 ab c3 ac c3 ad c3 ae c3 af
000160 c3 b0 c3 b1 c3 b2 c3 b3 c3 b4 c3 b5 c3 b6 c3 b7
000170 c3 b8 c3 b9 c3 ba c3 bb c3 bc c3 bd c3 be c3 bf
000180

The correct way:
Code:
$ seq 0 255 | LC_CTYPE=C awk '{printf "%c", $0}' | od -Ax -tx1
000000 00 01 02 03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
000010 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f
000020 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
000030 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
000040 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
000050 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
000060 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
000070 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f
000080 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f
000090 90 91 92 93 94 95 96 97 98 99 9a 9b 9c 9d 9e 9f
0000a0 a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa ab ac ad ae af
0000b0 b0 b1 b2 b3 b4 b5 b6 b7 b8 b9 ba bb bc bd be bf
0000c0 c0 c1 c2 c3 c4 c5 c6 c7 c8 c9 ca cb cc cd ce cf
0000d0 d0 d1 d2 d3 d4 d5 d6 d7 d8 d9 da db dc dd de df
0000e0 e0 e1 e2 e3 e4 e5 e6 e7 e8 e9 ea eb ec ed ee ef
0000f0 f0 f1 f2 f3 f4 f5 f6 f7 f8 f9 fa fb fc fd fe ff
000100

Regards,
Alister

Last edited by alister; 10-14-2013 at 02:58 PM.. Reason: Changed LANG to LC_CTYPE
This User Gave Thanks to alister For This Post:
# 6  
Old 10-14-2013
OK a few tests, OSX 10.7.5, default bash terminal:-

The first block is MadeInGermany's, the last three characters should be newlines not NULLs.
Second is alister's and only allows KB input much akin to INKEY$ on this tool.
Third is mine unchanged from the original post, last three characters correct.
Lastly a real hexdump command showing the last three characters.

Alister, the original code I found did include LANG=C but I removed it. Thanks for the info...

The test binary code is attached as a "txt" file...
Code:
Last login: Mon Oct 14 18:32:36 on ttys000
AMIGA:barrywalker~> ./hex_dump3.sh /tmp/bin.dat
 20  00  20  09  00  20  00  00  01  02  03  04  05  06  07  08  09  00  0B  0C 
 0D  0E  0F  10  11  12  13  14  15  16  17  18  19  1A  1B  1C  1D  1E  1F  20 
 21  22  23  24  25  26  27  28  29  2A  2B  2C  2D  2E  2F  30  31  32  33  34 
 35  36  37  38  39  3A  3B  3C  3D  3E  3F  40  41  42  43  44  45  46  47  48 
 49  4A  4B  4C  4D  4E  4F  50  51  52  53  54  55  56  57  58  59  5A  5B  5C 
 5D  5E  5F  60  61  62  63  64  65  66  67  68  69  6A  6B  6C  6D  6E  6F  70 
 71  72  73  74  75  76  77  78  79  7A  7B  7C  7D  7E  7F  80  81  82  83  84 
 85  86  87  88  89  8A  8B  8C  8D  8E  8F  90  91  92  93  94  95  96  97  98 
 99  9A  9B  9C  9D  9E  9F  A0  A1  A2  A3  A4  A5  A6  A7  A8  A9  AA  AB  AC 
 AD  AE  AF  B0  B1  B2  B3  B4  B5  B6  B7  B8  B9  BA  BB  BC  BD  BE  BF  C0 
 C1  C2  C3  C4  C5  C6  C7  C8  C9  CA  CB  CC  CD  CE  CF  D0  D1  D2  D3  D4 
 D5  D6  D7  D8  D9  DA  DB  DC  DD  DE  DF  E0  E1  E2  E3  E4  E5  E6  E7  E8 
 E9  EA  EB  EC  ED  EE  EF  F0  F1  F2  F3  F4  F5  F6  F7  F8  F9  FA  FB  FC 
 FD  FE  FF  00  00  00 
AMIGA:barrywalker~> ./hex_dump4.sh /tmp/bin.dat
71
77
65
72
74
79
75
69
6F
70

AMIGA:barrywalker~> ./hex_dump5.sh /tmp/bin.dat
 20  0A  20  09  0A  20  0A  00  01  02  03  04  05  06  07  08  09  0A  0B  0C 
 0D  0E  0F  10  11  12  13  14  15  16  17  18  19  1A  1B  1C  1D  1E  1F  20 
 21  22  23  24  25  26  27  28  29  2A  2B  2C  2D  2E  2F  30  31  32  33  34 
 35  36  37  38  39  3A  3B  3C  3D  3E  3F  40  41  42  43  44  45  46  47  48 
 49  4A  4B  4C  4D  4E  4F  50  51  52  53  54  55  56  57  58  59  5A  5B  5C 
 5D  5E  5F  60  61  62  63  64  65  66  67  68  69  6A  6B  6C  6D  6E  6F  70 
 71  72  73  74  75  76  77  78  79  7A  7B  7C  7D  7E  7F  80  81  82  83  84 
 85  86  87  88  89  8A  8B  8C  8D  8E  8F  90  91  92  93  94  95  96  97  98 
 99  9A  9B  9C  9D  9E  9F  A0  A1  A2  A3  A4  A5  A6  A7  A8  A9  AA  AB  AC 
 AD  AE  AF  B0  B1  B2  B3  B4  B5  B6  B7  B8  B9  BA  BB  BC  BD  BE  BF  C0 
 C1  C2  C3  C4  C5  C6  C7  C8  C9  CA  CB  CC  CD  CE  CF  D0  D1  D2  D3  D4 
 D5  D6  D7  D8  D9  DA  DB  DC  DD  DE  DF  E0  E1  E2  E3  E4  E5  E6  E7  E8 
 E9  EA  EB  EC  ED  EE  EF  F0  F1  F2  F3  F4  F5  F6  F7  F8  F9  FA  FB  FC 
 FD  FE  FF  0A  0A  0A 
AMIGA:barrywalker~> hexdump -C /tmp/bin.dat
00000000  20 0a 20 09 0a 20 0a 00  01 02 03 04 05 06 07 08  | . .. ..........|
00000010  09 0a 0b 0c 0d 0e 0f 10  11 12 13 14 15 16 17 18  |................|
00000020  19 1a 1b 1c 1d 1e 1f 20  21 22 23 24 25 26 27 28  |....... !"#$%&'(|
00000030  29 2a 2b 2c 2d 2e 2f 30  31 32 33 34 35 36 37 38  |)*+,-./012345678|
00000040  39 3a 3b 3c 3d 3e 3f 40  41 42 43 44 45 46 47 48  |9:;<=>?@ABCDEFGH|
00000050  49 4a 4b 4c 4d 4e 4f 50  51 52 53 54 55 56 57 58  |IJKLMNOPQRSTUVWX|
00000060  59 5a 5b 5c 5d 5e 5f 60  61 62 63 64 65 66 67 68  |YZ[\]^_`abcdefgh|
00000070  69 6a 6b 6c 6d 6e 6f 70  71 72 73 74 75 76 77 78  |ijklmnopqrstuvwx|
00000080  79 7a 7b 7c 7d 7e 7f 80  81 82 83 84 85 86 87 88  |yz{|}~..........|
00000090  89 8a 8b 8c 8d 8e 8f 90  91 92 93 94 95 96 97 98  |................|
000000a0  99 9a 9b 9c 9d 9e 9f a0  a1 a2 a3 a4 a5 a6 a7 a8  |................|
000000b0  a9 aa ab ac ad ae af b0  b1 b2 b3 b4 b5 b6 b7 b8  |................|
000000c0  b9 ba bb bc bd be bf c0  c1 c2 c3 c4 c5 c6 c7 c8  |................|
000000d0  c9 ca cb cc cd ce cf d0  d1 d2 d3 d4 d5 d6 d7 d8  |................|
000000e0  d9 da db dc dd de df e0  e1 e2 e3 e4 e5 e6 e7 e8  |................|
000000f0  e9 ea eb ec ed ee ef f0  f1 f2 f3 f4 f5 f6 f7 f8  |................|
00000100  f9 fa fb fc fd fe ff 0a  0a 0a                    |..........|
0000010a
AMIGA:barrywalker~>

EDIT:
I forgot to add that I want to use the bash builtins only and not rely on transient commands like od,
xxd or hexdump to get my required results purely as an exercise to learn more about the limitations
of bash, (or any shell for that matter), scripting... You guys are a godsend to people like me and
certainly have put me on the straight and narrow...

Thank to all...

Last edited by wisecracker; 10-14-2013 at 03:34 PM..
# 7  
Old 10-14-2013
I deleted the -d '' option, assuming that it is redundant with IFS="".
But in fact both are needed. Why?
Code:
while IFS="" read -d '' -r -n 1 char

I haven't understood the formatting code.
Apparently it can boil down to
Code:
#!/bin/bash --posix
# bash-hexdump

while IFS="" read -d '' -r -n 1 char
do
    printf " %02X " "'$char"
done <"$1"
echo ""


Last edited by MadeInGermany; 10-14-2013 at 04:10 PM..
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How to use "mailx" command to do e-mail reading the input file containing email address, where column 1 has name and column 2 containing “To” e-mail address and column 3 contains “cc” e-mail address to include with same email. Sample input file, email.txt Below is an sample code where... (2 Replies)
Discussion started by: asjaiswal
2 Replies

4. Shell Programming and Scripting

Read from "list1" and list matches in "list2"

I want to print any matching IP addresse in List1 with List 2; List 1 List of IP addresses; 161.85.58.210 250.57.15.129 217.23.162.249 74.76.129.101 30.221.177.237 3.147.200.59 170.58.142.64 127.65.109.33 150.167.242.146 223.3.20.186 25.181.180.99 2.55.199.32 (3 Replies)
Discussion started by: lewk
3 Replies

5. Shell Programming and Scripting

awk command to replace ";" with "|" and ""|" at diferent places in line of file

Hi, I have line in input file as below: 3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL My expected output for line in the file must be : "1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL" Can someone... (7 Replies)
Discussion started by: shis100
7 Replies

6. Shell Programming and Scripting

read -p "prompt text" foo say "read: bad option(s)" in Bourne-Shell

Hallo, i need a Prompting read in my script: read -p "Enter your command: " command But i always get this Error: -p: is not an identifier When I run these in c-shell i get this error /usr/bin/read: read: bad option(s) How can I use a Prompt in the read command? (9 Replies)
Discussion started by: wiseguy
9 Replies

7. UNIX for Dummies Questions & Answers

Explain the line "mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'`"

Hi Friends, Can any of you explain me about the below line of code? mn_code=`env|grep "..mn"|awk -F"=" '{print $2}'` Im not able to understand, what exactly it is doing :confused: Any help would be useful for me. Lokesha (4 Replies)
Discussion started by: Lokesha
4 Replies

8. UNIX for Dummies Questions & Answers

No utpmx entry: you must exec "login" from lowest level "shell"

Hi I have installed solaris 10 on an intel machine. Logged in as root. In CDE, i open terminal session, type login alex (normal user account) and password and i get this message No utpmx entry: you must exec "login" from lowest level "shell" :confused: What i want is: open various... (0 Replies)
Discussion started by: peterpan
0 Replies

9. Shell Programming and Scripting

how to request a "read" or "delivered" receipt for mails

Dears, I've written a script which allows me to send mails in different formats with different attaches. Now I still want to add a feature to this script. My users would like to be able to receive a "read" or "delivered" receipt for their mails. The script send mails on behalve of an specific... (1 Reply)
Discussion started by: plelie2
1 Replies
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