Sponsored Content
Full Discussion: Deciphering AWK code
Top Forums UNIX for Beginners Questions & Answers Deciphering AWK code Post 303041581 by RudiC on Thursday 28th of November 2019 05:45:01 AM
Old 11-28-2019
Here you are:
Code:
awk '
!(a[$1])        {a[$1]=$0                       # if array element indexed by $1 is unset or 0, set it to
                                                # the line (i.e. collect first occurrences of $1)
                 next                           # continue with the next input line
                }
a[$1]           {w    = $1                      # if set, save $1 in temp variable
                 $1   = ""                      # and remove it (but leave FS intact)
                 a[w] = a[w] $0                 # then append line to resp. array element
                }
END             {for (i in a) print a[i]        # print all elements containing collected lines
                                                # be aware that the order of elements is unspecified 
                }
' FS="\t" OFS="\t" file

Please note how consistent structuring (e.g. indentation) of the code helps in reading / understanding / seeing patterns in it.
These 4 Users Gave Thanks to RudiC For This Post:
 

9 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Help deciphering script

There are files on a remote server with the file name ending in "mm-dd-yy.txt". The script I am running is: mls "Daily_Service_Text_File_*" /my/local/dir/Filelisting.txt nawk -F_ -f file.awk /my/local/dir/Filelisting.txt | sort -k1n | cut -f2- | tail -1 It worked up too "12-31-07.txt" but... (3 Replies)
Discussion started by: bbbngowc
3 Replies

2. Shell Programming and Scripting

Help deciphering FTP get perl script

I found this very useful perl script that will check a remote ftp server, search for files of a specific time and get them. When I run the script it works, but it gave me the following error: Couldn't get filename_12-13-07.txt Bad file number What in this script would cause this? I know... (2 Replies)
Discussion started by: bbbngowc
2 Replies

3. UNIX for Dummies Questions & Answers

Deciphering the Code

Hi people I am trying to learn this code and see how it relates to the old DOS days. I have a line of code that I am not sure what the first part does. Any help will be greatly appreciated. It is from a Save command that is used to backup files to a directory. It goes like this if ;then... (10 Replies)
Discussion started by: coyote1967
10 Replies

4. Shell Programming and Scripting

Deciphering strings or variable values

Hi, I have a script at the moment of which reads in simply what the latest version is within a folder i.e. v001, v002, v003 etc and then stores this latest version in a variable i.e. $LATEST would echo v003. I have then cut this string so that I only consider the 003 part. I would then like to... (3 Replies)
Discussion started by: cyberfrog
3 Replies

5. UNIX for Dummies Questions & Answers

Need help deciphering this

I'm reading about command substitutions and came across this little function in my book: function lsd { date=$1 ls -l |grep -i "^.\{42\}$date"|cut -c55- } it's a little example which is supposed to select files by modification date, given as an argument to the function. I... (3 Replies)
Discussion started by: Straitsfan
3 Replies

6. Programming

Some help with Perl please (deciphering)

I am trying to simplify the coding in a script I was given, but it was written 7-10 years ago and is pretty complicated. below is a tidbit, if someone can break it down for me I would appreciate it. sub ParseText { my ($line, $key, $value, $sub, $script); foreach $line (@_)... (0 Replies)
Discussion started by: callyvan
0 Replies

7. Shell Programming and Scripting

need help deciphering this if statement

I'm going through my bash book and came across this if statment. if *$)" ]; then the book says that the grep expression means "an initial dash followed by a digit" (which I understand) "optionally followed by one or more digits" That's the part I can't figure out -- I know the * is a... (8 Replies)
Discussion started by: Straitsfan
8 Replies

8. Shell Programming and Scripting

Help with AWK Code

hello, I would appreciate a little assistance with a process I'm trying to automate. I have several files that are zipped in central location, all follow the same naming conventions i.e (file 1, file 2, etc). what i would like to do is unzip the files and combined them into one file, basically... (2 Replies)
Discussion started by: mrn970
2 Replies

9. Programming

Deciphering a tag character string

I have a string, eg 7f30.3 and I want to store things in the following way npos = 7 decform = true width = 30 ndp = 3 I need to read each character one by one. I am coding in fortran but I can try to code it should answer be given in C in the above way. (2 Replies)
Discussion started by: kristinu
2 Replies
array(n)						       Tcl Built-In Commands							  array(n)

__________________________________________________________________________________________________________________________________________________

NAME
array - Manipulate array variables SYNOPSIS
array option arrayName ?arg arg ...? _________________________________________________________________ DESCRIPTION
This command performs one of several operations on the variable given by arrayName. Unless otherwise specified for individual commands below, arrayName must be the name of an existing array variable. The option argument determines what action is carried out by the command. The legal options (which may be abbreviated) are: array anymore arrayName searchId Returns 1 if there are any more elements left to be processed in an array search, 0 if all elements have already been returned. SearchId indicates which search on arrayName to check, and must have been the return value from a previous invocation of array startsearch. This option is particularly useful if an array has an element with an empty name, since the return value from array nextelement won't indicate whether the search has been completed. array donesearch arrayName searchId This command terminates an array search and destroys all the state associated with that search. SearchId indicates which search on arrayName to destroy, and must have been the return value from a previous invocation of array startsearch. Returns an empty string. array exists arrayName Returns 1 if arrayName is an array variable, 0 if there is no variable by that name or if it is a scalar variable. array get arrayName ?pattern? Returns a list containing pairs of elements. The first element in each pair is the name of an element in arrayName and the second element of each pair is the value of the array element. The order of the pairs is undefined. If pattern is not specified, then all of the elements of the array are included in the result. If pattern is specified, then only those elements whose names match pat- tern (using the matching rules of string match) are included. If arrayName isn't the name of an array variable, or if the array contains no elements, then an empty list is returned. array names arrayName ?pattern? Returns a list containing the names of all of the elements in the array that match pattern (using the matching rules of string match). If pattern is omitted then the command returns all of the element names in the array. If there are no (matching) elements in the array, or if arrayName isn't the name of an array variable, then an empty string is returned. array nextelement arrayName searchId Returns the name of the next element in arrayName, or an empty string if all elements of arrayName have already been returned in this search. The searchId argument identifies the search, and must have been the return value of an array startsearch command. Warning: if elements are added to or deleted from the array, then all searches are automatically terminated just as if array done- search had been invoked; this will cause array nextelement operations to fail for those searches. array set arrayName list Sets the values of one or more elements in arrayName. list must have a form like that returned by array get, consisting of an even number of elements. Each odd-numbered element in list is treated as an element name within arrayName, and the following element in list is used as a new value for that array element. If the variable arrayName does not already exist and list is empty, arrayName is created with an empty array value. array size arrayName Returns a decimal string giving the number of elements in the array. If arrayName isn't the name of an array then 0 is returned. array startsearch arrayName This command initializes an element-by-element search through the array given by arrayName, such that invocations of the array nex- telement command will return the names of the individual elements in the array. When the search has been completed, the array done- search command should be invoked. The return value is a search identifier that must be used in array nextelement and array done- search commands; it allows multiple searches to be underway simultaneously for the same array. | array unset arrayName ?pattern? | Unsets all of the elements in the array that match pattern (using the matching rules of string match). If arrayName isn't the name | of an array variable or there are no matching elements in the array, then an empty string is returned. If pattern is omitted and is | it an array variable, then the command unsets the entire array. KEYWORDS
array, element names, search Tcl 8.3 array(n)
All times are GMT -4. The time now is 09:01 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy