Shell Programming and Scripting

-> awk -F, '{$41=""}1' OFS="," file.csv
+ awk -F, {$41=""}1 OFS=, file.csv
awk: syntax error near line 1
awk: bailing out near line 1

-> nawk -F, '{$41=""}1' OFS="," file.csv
+ nawk -F, {$41=""}1 OFS=, file.csv
1,2,3,4,5,6,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
1,2,3,4,5,6,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
1,2,3,4,5,6,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
1,2,3,4,5,6,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

 
"The standard does not require recomputation of $0 when NF is assigned. However, it does if you assign to a field beyond NF (which also recomputes NF)."

$0 == "a,b,c,d,e,f"
$NF == "f"
NF == 6
$10="g"
NF == 10  # NF has been recomputed
$NF == "g"
$0 == "a,b,c,d,e,f,,,,g"  # $0 has been recomputed to include null fields between the old value of $NF and the new.

$0 == "a b        c       d       e       f"
$NF == "f"
NF == 6
$10="g"
NF == 10  # NF has been recomputed
$NF == "g"
$0 == "a b c d e f    g"  # $0 has been recomputed to include null fields between the old value of $NF and the new.
                          # Note that the spaces between fields have been compressed to a single space.
                          # Also, this is not reversible; once done, if you did not save the original value of $0,
                          # it cannot be restored.

$0 == "a b        c       d       e       f"
$1=$1
$0 == "a b c d e f"  # $0 has been recomputed, the spaces between fields have been replaced by the value of OFS,
                     # but NF remains unchanged as we did not extend the number of fields in any way.

Object Type,Object Subtype,Object Name,CEMLI Type,Owner,Location,Created By, Creation Date, Updated By, Update Date, LastRecorded Usage
DB_OBJECT,ALERT,@GEPSAlphaPOSOEAInotification,CONFIGURATION,FND,ALR_ALERTS,CONCURRENT_MGR,10-Feb-10,CONCURRENT_MGR,test,

-> awk -F, '{NF=41}1' OFS="," test.csv > result.csv
-> more result.csv
Object Type,Object Subtype,Object Name,CEMLI Type,Owner,Location,Created By, Creation Date, Updated By, Update Date, LastRecorded Usage
, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
DB_OBJECT,ALERT,@GEPSAlphaPOSOEAInotification,CONFIGURATION,FND,ALR_ALERTS,CONCURRENT_MGR,10-Feb-10,CONCURRENT_MGR,test,
, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,

awk -F, '{$41=""}1' OFS="," file

head -3 test.csv |  od -An -t x1

-> head -3 test.csv |  od -An -t x1 
 4f 62 6a 65 63 74 20 54 79 70 65 2c 4f 62 6a 65
 63 74 20 53 75 62 74 79 70 65 2c 4f 62 6a 65 63
 74 20 4e 61 6d 65 2c 43 45 4d 4c 49 20 54 79 70
 65 2c 4f 77 6e 65 72 2c 4c 6f 63 61 74 69 6f 6e
 2c 43 72 65 61 74 65 64 20 42 79 2c 20 43 72 65
 61 74 69 6f 6e 20 44 61 74 65 2c 20 55 70 64 61
 74 65 64 20 42 79 2c 20 55 70 64 61 74 65 20 44
 61 74 65 2c 20 4c 61 73 74 52 65 63 6f 72 64 65
 64 20 55 73 61 67 65 0d 0a 44 42 5f 4f 42 4a 45
 43 54 2c 41 4c 45 52 54 2c 40 47 45 50 53 20 41
 6c 70 68 61 50 4f 53 4f 20 45 41 49 20 6e 6f 74
 69 66 69 63 61 74 69 6f 6e 2c 43 4f 4e 46 49 47
 55 52 41 54 49 4f 4e 2c 46 4e 44 2c 41 4c 52 5f
 41 4c 45 52 54 53 2c 43 4f 4e 43 55 52 52 45 4e
 54 5f 4d 47 52 2c 31 30 2d 46 65 62 2d 31 30 2c
 43 4f 4e 43 55 52 52 45 4e 54 5f 4d 47 52 2c 74
 65 73 74 2c 0d 0a 44 42 5f 4f 42 4a 45 43 54 2c
 41 4c 45 52 54 2c 40 47 45 50 53 20 41 6c 70 68
 61 50 4f 53 4f 20 53 75 70 70 6c 20 53 69 74 65
 20 73 65 74 75 70 20 61 6c 65 72 74 20 6e 6f 74
 69 66 79 2c 43 4f 4e 46 49 47 55 52 41 54 49 4f
 4e 2c 46 4e 44 2c 41 4c 52 5f 41 4c 45 52 54 53
 2c 43 4f 4e 43 55 52 52 45 4e 54 5f 4d 47 52 2c
 32 39 2d 4a 61 6e 2d 31 30 2c 43 4f 4e 43 55 52
 52 45 4e 54 5f 4d 47 52 2c 20 2c 0d 0a