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Process Help DMEDIT - edit a file in-place |
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Process Name |
Menu Path |
Link to Command Table |
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DMEDIT |
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Introduction
Edits a file in-place, that is without creating a new copy.
How to use
The edit functions are selected by entering a single character command. Where required, commands prompt for extra information. The functions available are:-
F List all field names.
C Change a field name.
L List a line or lines of data.
D Delete a line or lines of data.
R Replace a data item over 1 or more lines.
S Search for a given data item.
H Provide help.
V Change default value of a field.
P Change last page/record.
E Exit from editor.
Thus the editor permits certain changes to the file Data Definition as well as to the data contained within the file. The C, R, S and V commands all work on fields, which are specified by the user. They may work on either numeric or alphanumeric fields; the type is detected by the editor. Only explicit (stored) fields may be edited. Attempts to edit implicit fields will produce an error message, causing the command to be abandoned.
Files, Fields and Parameters
Input Files
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Name |
Description |
I/O Status |
Required |
Type |
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IN |
File to be edited. |
Input |
Yes |
Undefined |
Output Files
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Name |
I/O Status |
Required |
Type |
Description |
Parameters
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Name |
Description |
Required |
Default |
Range |
Values |
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Send a complete record of the edit session to the printer or print file if ECHO=1 , PRINT=2. |
No |
0 |
0,2 |
0,1,2 |
Notes
Line Numbers are integers, entered in response to the FROM and TO prompts.
The TO number must be greater than or equal to the FROM.
If FROM is greater than the last line, the message:-
>>> PAST END OF FILE <<<
is produced and the command abandoned. If FROM is entered as 0, the current line (last one searched, listed etc) is used.
If TO is entered as 0, a single line is assumed. If TO is given beyond the end of file, it will be set to the last record.
Errors in entering FROM and TO will cause the command to be abandoned.
Alphanumeric Values are not enclosed in quotes ('). If they are shorter than the field length, they will be blank padded. If they are longer, they will be truncated.
Page/Record numbers are calculated as follows:-
Run the edit process with parameter @DEBUG=1. This will display the required values NPST (start page number for data) and NLRP (number of logical records/page). Locate the last line in the file containing good data (NLASTL). Then:-
NLASTP = NPST + (NLASTL-1)*NLRP + 1
NLASTR = NLASTL - (NLASTP-NPST)*NLRP
DMEDIT should not be used on an index file. If it is, the actual index file will be edited, not the files referred to. It is usually better to re-create the index.
Deleted records are still maintained in the file after editing, although they are not accessible. They may be removed by use of the COPY process.DMEDIT may not be used to insert records. This may be done by use of the EXTEND process on a file with line numbers (COPYNR process), followed by SORT on the RECORDNO field.
>DMEDIT may be aborted without change to the file by typing ! in response to the EDIT > prompt.
Example
!DMEDIT &IN(ASSAYS)
>>> EDITING FILE ASSAYS <<<
=============================
(Listing of available commands)
EDIT > L<return>
>>> LIST LINES
FROM > 1<return>
TO > 3<return>
1>>BH0001 0.000000 12.000000 0.000000 0.000000
2>>BH0001 12.000000 14.000000 0.500000 0.100000
3>>BH0001 14.000000 16.300000 1.200000 0.530000
EDIT > R<return>
>>> REPLACE DATA
FIELD > Cu<return>
THIS IS A NUMERIC FIELD
VALUE > 0.3<return>
FROM > 1<return>
TO > 1<return>
EDIT > L<return>
>>> LIST LINES
FROM > 1<return>
TO > 3<return>
1>>BH0001 0.000000 12.000000 0.300000 0.000000
2>>BH0001 12.000000 14.000000 0.500000 0.100000
3>>BH0001 14.000000 16.300000 1.200000 0.530000
EDIT > D<return>
>>> DELETE LINES
FROM > 2<return>
TO > 2<return>
CONFIRM ? OK<return>
EDIT > L<return>
>>> LIST LINES
FROM > 1<return>
TO > 3<return>
1>>BH0001 0.000000 12.000000 0.300000 0.000000
3>>BH0001 14.000000 16.300000 1.200000 0.530000
EDIT > E<return>
>>> >>> EDIT COMPLETED <<< <<<
Error and Warning Messages
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Message |
Description |
Solution |
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>>> ILLEGAL COMMAND <<< |
Only C, D, E, F, H, L, P, R, S and V are valid commands.
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>>> FIELD NOT FOUND IN FILE <<< |
Field name requested in the C, R, S or V command does not exist in the file being edited.
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>>> FIELD ALREADY EXISTS <<< |
The new field name specified in the C command is already in the file. |
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>>> FIELD IS IMPLICIT - CANNOT BE EDITED <<< |
Only explicit fields can be edited. |
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>>> ILLEGAL LINE NUMBER <<< |
An illegal line number has been specified in the D, L, R, S or V command. |
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