10 More Discussions You Might Find Interesting
1. UNIX for Beginners Questions & Answers
Hi, can some some help to get me the right results,
I have few text files, need to grep few columns from each file and get the results in one row with comma separated.
my code is
#folder=/nz/kit/log/backupsvr
folder=/export/home/nz/valai/tmpfiles/
echo $folder
for entry in `ls... (4 Replies)
Discussion started by: ValaiG
4 Replies
2. Shell Programming and Scripting
I can not figure out how to set the Output filed separator in awk when using printf.
Example:
cat file
some data
here_is_more information
Requested output
some------------data
her_is_more-----information
Here are some that does not work:
awk '{printf "%-15s %s\n",$1,$2}' OFS="-" file... (9 Replies)
Discussion started by: Jotne
9 Replies
3. Shell Programming and Scripting
Hi Experts ,
file :
- How to construct the awk filed separator so that $1, $2 $3 , can be assigned to the each "" range.
I am trying : awk -F"]" '{print $1}'
but it is printing the entire file. Not first field.
The desired output needed for first field... (9 Replies)
Discussion started by: rveri
9 Replies
4. Shell Programming and Scripting
I need to set awk field separator to ";", but I need to avoid ";EXT".
so that
echo a;b;c;EXTd;e;f | awk -F";" '{print $3}'
would give "c;EXTd" (2 Replies)
Discussion started by: locoroco
2 Replies
5. UNIX for Dummies Questions & Answers
In awk, how do I print all fields with a specified output field separator?
I have tried the following, which does not print the output FS:
echo a b c d | awk 'BEGIN{OFS = ";"}{print $0}' (3 Replies)
Discussion started by: locoroco
3 Replies
6. Shell Programming and Scripting
I am using this code to insert something into a csv file:
awk -F";" -v url=$url -v nr=$nr 'NR==nr{$2=url$2}1' file
Why do I get the output
field1 field2
instead of
field1;field2
I have given -F";", so the field separator should surely be ";". (1 Reply)
Discussion started by: locoroco
1 Replies
7. Shell Programming and Scripting
Hi, all
I need to get fields in a line that are separated by commas, some of the fields are enclosed with double quotes, and they are supposed to be treated as a single field even if there are commas inside the quotes.
sample input:
for this line, 5 fields are supposed to be extracted, they... (8 Replies)
Discussion started by: kevintse
8 Replies
8. Shell Programming and Scripting
Hi;
i have a file and i want to get;
- If the last word in line 14 is NOT equal to "Set."; then print 2nd, 3rd, 4th and 5th values of 3rd line.
and my code is:
nawk 'NR==14 {if ($NF!="Set.") (NR==3{print $2,$3,$4,$5}) }' file.txt
but no result?? :confused::(:confused::( (4 Replies)
Discussion started by: gc_sw
4 Replies
9. Shell Programming and Scripting
Hi All,
I was wondering if anyone knew how to dynamically change the FS in awk to accept vairiable containing a field separator. the current code is as below and does not work when i introduce the dynamic FS change :-(
validate_source_file()
{
source_file=$1
... (2 Replies)
Discussion started by: satnamx
2 Replies
10. UNIX for Dummies Questions & Answers
Hi Friends,
Scripting newb here. So I'm trying to create a geektool script that uses awk and printf to output certain fields from top (namely command, cpu%, rsize, pid and time, in that order).
Here's the input from the top process that I'm putting into awk:
PID COMMAND %CPU ... (3 Replies)
Discussion started by: thom.mattson
3 Replies
A2P(1) Perl Programmers Reference Guide A2P(1)
NAME
a2p - Awk to Perl translator
SYNOPSIS
a2p [options] filename
DESCRIPTION
A2p takes an awk script specified on the command line (or from standard input) and produces a comparable perl script on the standard out-
put.
Options
Options include:
-D<number>
sets debugging flags.
-F<character>
tells a2p that this awk script is always invoked with this -F switch.
-n<fieldlist>
specifies the names of the input fields if input does not have to be split into an array. If you were translating an awk script that
processes the password file, you might say:
a2p -7 -nlogin.password.uid.gid.gcos.shell.home
Any delimiter can be used to separate the field names.
-<number>
causes a2p to assume that input will always have that many fields.
-o tells a2p to use old awk behavior. The only current differences are:
o Old awk always has a line loop, even if there are no line actions, whereas new awk does not.
o In old awk, sprintf is extremely greedy about its arguments. For example, given the statement
print sprintf(some_args), extra_args;
old awk considers extra_args to be arguments to "sprintf"; new awk considers them arguments to "print".
"Considerations"
A2p cannot do as good a job translating as a human would, but it usually does pretty well. There are some areas where you may want to
examine the perl script produced and tweak it some. Here are some of them, in no particular order.
There is an awk idiom of putting int() around a string expression to force numeric interpretation, even though the argument is always inte-
ger anyway. This is generally unneeded in perl, but a2p can't tell if the argument is always going to be integer, so it leaves it in. You
may wish to remove it.
Perl differentiates numeric comparison from string comparison. Awk has one operator for both that decides at run time which comparison to
do. A2p does not try to do a complete job of awk emulation at this point. Instead it guesses which one you want. It's almost always
right, but it can be spoofed. All such guesses are marked with the comment ""#???"". You should go through and check them. You might
want to run at least once with the -w switch to perl, which will warn you if you use == where you should have used eq.
Perl does not attempt to emulate the behavior of awk in which nonexistent array elements spring into existence simply by being referenced.
If somehow you are relying on this mechanism to create null entries for a subsequent for...in, they won't be there in perl.
If a2p makes a split line that assigns to a list of variables that looks like (Fld1, Fld2, Fld3...) you may want to rerun a2p using the -n
option mentioned above. This will let you name the fields throughout the script. If it splits to an array instead, the script is probably
referring to the number of fields somewhere.
The exit statement in awk doesn't necessarily exit; it goes to the END block if there is one. Awk scripts that do contortions within the
END block to bypass the block under such circumstances can be simplified by removing the conditional in the END block and just exiting
directly from the perl script.
Perl has two kinds of array, numerically-indexed and associative. Perl associative arrays are called "hashes". Awk arrays are usually
translated to hashes, but if you happen to know that the index is always going to be numeric you could change the {...} to [...]. Itera-
tion over a hash is done using the keys() function, but iteration over an array is NOT. You might need to modify any loop that iterates
over such an array.
Awk starts by assuming OFMT has the value %.6g. Perl starts by assuming its equivalent, $#, to have the value %.20g. You'll want to set
$# explicitly if you use the default value of OFMT.
Near the top of the line loop will be the split operation that is implicit in the awk script. There are times when you can move this down
past some conditionals that test the entire record so that the split is not done as often.
For aesthetic reasons you may wish to change the array base $[ from 1 back to perl's default of 0, but remember to change all array sub-
scripts AND all substr() and index() operations to match.
Cute comments that say "# Here is a workaround because awk is dumb" are passed through unmodified.
Awk scripts are often embedded in a shell script that pipes stuff into and out of awk. Often the shell script wrapper can be incorporated
into the perl script, since perl can start up pipes into and out of itself, and can do other things that awk can't do by itself.
Scripts that refer to the special variables RSTART and RLENGTH can often be simplified by referring to the variables $`, $& and $', as long
as they are within the scope of the pattern match that sets them.
The produced perl script may have subroutines defined to deal with awk's semantics regarding getline and print. Since a2p usually picks
correctness over efficiency. it is almost always possible to rewrite such code to be more efficient by discarding the semantic sugar.
For efficiency, you may wish to remove the keyword from any return statement that is the last statement executed in a subroutine. A2p
catches the most common case, but doesn't analyze embedded blocks for subtler cases.
ARGV[0] translates to $ARGV0, but ARGV[n] translates to $ARGV[$n]. A loop that tries to iterate over ARGV[0] won't find it.
ENVIRONMENT
A2p uses no environment variables.
AUTHOR
Larry Wall <larry@wall.org>
FILES
SEE ALSO
perl The perl compiler/interpreter
s2p sed to perl translator
DIAGNOSTICS
BUGS
It would be possible to emulate awk's behavior in selecting string versus numeric operations at run time by inspection of the operands, but
it would be gross and inefficient. Besides, a2p almost always guesses right.
Storage for the awk syntax tree is currently static, and can run out.
perl v5.8.0 2002-06-01 A2P(1)