Sponsored Content
Top Forums Shell Programming and Scripting replacing field in specific line in a file Post 302447938 by Corona688 on Tuesday 24th of August 2010 06:26:08 PM
Old 08-24-2010
The problem is that file I/O has no "insert" operation: If the new data is a different length than the old you need to rewrite everything after the change.

There's way better, faster, and simpler ways than the 'cut' utility to read fields from a data file, but it's difficult to help without seeing the rest of your program. It'd also tell me what other fields from that line you have, since just knowing the balance isn't enough to find and edit that exact line...
This User Gave Thanks to Corona688 For This Post:
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Replacing the last field of a line.

Hi, I wrote a script which extracts data from 2 tables (joining the tables together) and outputs the fields to a csv file. the output may look something like scenario 1: a,b,c,d,1,2,3,4 or scenario 2: a,b,c,d,,,, now, in the second scenario, there are some empty fields at the end of... (3 Replies)
Discussion started by: Darek
3 Replies

2. UNIX for Dummies Questions & Answers

replacing string in a column on a specific line

hi, i currently have a file with columns similar to this customer name owed CID123 John 300 CID342 harry 500 at present i use use awk to find the amount owed by the customer using the customer ID (CID). if the customer spends more money how would i go about using sed/awk etc to... (2 Replies)
Discussion started by: skinnygav
2 Replies

3. Shell Programming and Scripting

How to append a character to the last but one field on a specific line?

Hi Guys, I have a file like this: aaa b c d e f fsss g h i k l qqq r t h n I want: aaa b c d e f fsss g h i k l qqq r t h , n ggg p t e d u qqq i o s , k (2 Replies)
Discussion started by: npatwardhan
2 Replies

4. Shell Programming and Scripting

SED Replacing all but one regex match on a line or specific matches

Hi, I'm attempting to rename some files that have spaces in them. Without linking sed commands together is it possible to replace the first three "." to " ". File.name.is.long.ext -> File name is long.ext I can get the desired effect with echo "File.name.is.long.ext" | sed 's/\./ /g;s/... (5 Replies)
Discussion started by: vectox
5 Replies

5. Shell Programming and Scripting

Using awk to read a specific line and a specific field on that line.

Say the input was as follows: Brat 20 x 1000 32rf Pour 15 p 1621 05pr Dart 10 z 1111 22xx My program prompts for an input, what I want is to use the input to locate a specific field. Like if I type in, "Pou" then it would return "Pour" and just "Pour" I currently have this line but it is... (6 Replies)
Discussion started by: Bungkai
6 Replies

6. Shell Programming and Scripting

Replace specific field on specific line sed or awk

I'm trying to update a text file via sed/awk, after a lot of searching I still can't find a code snippet that I can get to work. Brief overview: I have user input a line to a variable, I then find a specific value in this line 10th field in this case. After asking for new input and doing some... (14 Replies)
Discussion started by: crownedzero
14 Replies

7. Shell Programming and Scripting

Update specific field in a line of text file

I have a text file like this: subject1:LecturerA:10 subject2:LecturerA:40 if I was given string in column 1 and 2 (which are subject 1 and LecturerA) , i need to update 3rd field of that line containing that given string , which is, number 10 need to be updated to 100 ,for example. The... (6 Replies)
Discussion started by: bmtoan
6 Replies

8. Shell Programming and Scripting

Replacing nth field with nth_text for each line in a file

Hi All, I am very new to shell scripting and tried to search this in the forum but no luck. Requirment: I have an input file which is comma separated. I need to replace the value in 4th column with another value. This has to happen for all the lines in the file. Sample data: Input... (2 Replies)
Discussion started by: arunkumarsd
2 Replies

9. Shell Programming and Scripting

Replacing entire fields with specific text at end or beginning of field

Greetings. I've got a csv file with data along these lines: Spumoni's Pizza Place, Placemats n Things, Just Lamps Counterfeit Dollars by Vinnie, Just Shades, Dollar StoreI want to replace the entire comma-delimited field if it matches something ending in "Place" or beginning with "Dollar",... (2 Replies)
Discussion started by: palmfrond
2 Replies

10. UNIX for Beginners Questions & Answers

How do you preserve the max length of a line after replacing a specific value?

I'm new with scripting and I can't seem to figure out what I should do to get the output that I want. My file content would be below. ID2|ID3 |ID4|ID5 | I'm trying to replace the field of ID3 which has a fixed length of 10 characters, for each entry I have placed on a .txt file... (5 Replies)
Discussion started by: asdfghjkl
5 Replies
cut(1)								   User Commands							    cut(1)

NAME
cut - cut out selected fields of each line of a file SYNOPSIS
cut -b list [-n] [file]... cut -c list [file]... cut -f list [-d delim] [-s] [file]... DESCRIPTION
Use the cut utility to cut out columns from a table or fields from each line of a file; in data base parlance, it implements the projection of a relation. The fields as specified by list can be fixed length, that is, character positions as on a punched card (-c option) or the length can vary from line to line and be marked with a field delimiter character like TAB (-f option). cut can be used as a filter. Either the -b, -c, or -f option must be specified. Use grep(1) to make horizontal ``cuts'' (by context) through a file, or paste(1) to put files together column-wise (that is, horizontally). To reorder columns in a table, use cut and paste. OPTIONS
The following options are supported: list A comma-separated or blank-character-separated list of integer field numbers (in increasing order), with optional - to indi- cate ranges (for instance, 1,4,7; 1-3,8; -5,10 (short for 1-5,10); or 3- (short for third through last field)). -b list The list following -b specifies byte positions (for instance, -b1-72 would pass the first 72 bytes of each line). When -b and -n are used together, list is adjusted so that no multi-byte character is split. -c list The list following -c specifies character positions (for instance, -c1-72 would pass the first 72 characters of each line). -d delim The character following -d is the field delimiter (-f option only). Default is tab. Space or other characters with special meaning to the shell must be quoted. delim can be a multi-byte character. -f list The list following -f is a list of fields assumed to be separated in the file by a delimiter character (see -d ); for instance, -f1,7 copies the first and seventh field only. Lines with no field delimiters will be passed through intact (useful for table subheadings), unless -s is specified. -n Do not split characters. When -b list and -n are used together, list is adjusted so that no multi-byte character is split. -s Suppresses lines with no delimiter characters in case of -f option. Unless specified, lines with no delimiters will be passed through untouched. OPERANDS
The following operands are supported: file A path name of an input file. If no file operands are specified, or if a file operand is -, the standard input will be used. USAGE
See largefile(5) for the description of the behavior of cut when encountering files greater than or equal to 2 Gbyte (2^31 bytes). EXAMPLES
Example 1 Mapping user IDs A mapping of user IDs to names follows: example% cut -d: -f1,5 /etc/passwd Example 2 Setting current login name To set name to current login name: example$ name=`who am i | cut -f1 -d' '` ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of cut: LANG, LC_ALL, LC_CTYPE, LC_MES- SAGES, and NLSPATH. EXIT STATUS
The following exit values are returned: 0 All input files were output successfully. >0 An error occurred. ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ |CSI |Enabled | +-----------------------------+-----------------------------+ |Interface Stability |Standard | +-----------------------------+-----------------------------+ SEE ALSO
grep(1), paste(1), attributes(5), environ(5), largefile(5), standards(5) DIAGNOSTICS
cut: -n may only be used with -b cut: -d may only be used with -f cut: -s may only be used with -f cut: cannot open <file> Either file cannot be read or does not exist. If multiple files are present, processing continues. cut: no delimiter specified Missing delim on -d option. cut: invalid delimiter cut: no list specified Missing list on -b, -c, or -f option. cut: invalid range specifier cut: too many ranges specified cut: range must be increasing cut: invalid character in range cut: internal error processing input cut: invalid multibyte character cut: unable to allocate enough memory SunOS 5.11 29 Apr 1999 cut(1)
All times are GMT -4. The time now is 10:18 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy