10 More Discussions You Might Find Interesting
1. UNIX for Beginners Questions & Answers
Hi All,
Would you guys help me?
I have a file that consists of several unstructured fields. in this file I will take the code field and count_berry field.
but the position of the count_berry field is always changing.the column for code is always structured, which is found in column 6
I have... (4 Replies)
Discussion started by: kivale
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2. Shell Programming and Scripting
Hello All,
I have developed a script which selects a particular filed from a file ,trims it,searches for a particular pattern and then mail it when found.
cat test_file.txt |sed -n '5,$p'|sed -e 's/ //g'|awk -F'|' '{if ($4 !="Alive") print $1,$2,$3,$4}' >> proc_not_alive.txt
It is... (4 Replies)
Discussion started by: karthik adiga
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3. Shell Programming and Scripting
Hi All,
I have the below Input:
1 700 1200 400 1300
2 2000 1000 2000 1500 600
3 1400 200 1000 1000 1200
4 1300 500 600 200
I want to modify the field 5 and field 4 as below.
If value in field 5 is null then value of field 4 should be in field 5. and then the value of... (12 Replies)
Discussion started by: am24
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4. UNIX for Dummies Questions & Answers
Need help in awk command.
Need to check 4th column of a file, if it is CAR then awk should print as is and if 4th column is not present, awk should print BIKE
Input File content :
1,abc,55,CAR
3,bb,dd,CAR
5,ddd,tttt
8,ee,55
---------------------
Out put will look like:
1,abc,55,CAR... (6 Replies)
Discussion started by: vegasluxor
6 Replies
5. Shell Programming and Scripting
Hi Friends,
I have an input file like this
cat input
chr1 100 200 1 2
chr1 120 130 na 1
chr1 140 160 1 na
chr1 170 180 na na
chr1 190 220 0 0
chr1 220 230 nd 1
chr2 330 400 1 nd
chr2 410 450 nd nd
chr3 500 700 1 1
I want to calculate the division of 4th and 5th columns. But, if... (3 Replies)
Discussion started by: jacobs.smith
3 Replies
6. Shell Programming and Scripting
Hello experts,
I'm stuck with this script for three days now. Here's what i need.
I need to split a large delimited (,) file into 2 files based on the value present in the last field.
Samp: Something.csv
bca,adc,asdf,123,12C
bca,adc,asdf,123,13C
def,adc,asdf,123,12A
I need this split... (6 Replies)
Discussion started by: shell_boy23
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7. Shell Programming and Scripting
Hi, I need little help with awk's if condition statement. I have following code:
$ ssh myRemotehost 'ps ww -fu tomcat ' | awk ' { if ($1 == "tomcat") print "tomcat (pid " $2 ") is running... "; else print "tomcat stopped or dead" }'
Prints:
tomcat stopped or dead
tomcat (pid 12345) is... (6 Replies)
Discussion started by: davidtd
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8. Shell Programming and Scripting
Hi Guys,
I just wanted to print all the lines execpt 1st and 3rd line. For that i wrote a awk command,
awk 'NR != 1 || NR != 3 {print $0}' c.out
the command is working if i give an equal to instead of not equal to.
In the case of not equal to, it gives me the entire file.
Can you... (18 Replies)
Discussion started by: mac4rfree
18 Replies
9. Shell Programming and Scripting
Hi all;
I'm stuck with this simple awk script,i need to group the lines which the position of 28 length 3 that contains "688" into 1 group and other than "688" into another group. My problem is the script only read other than "688" and ignores the lines which contains "688".
The file look... (2 Replies)
Discussion started by: ashikin_8119
2 Replies
10. Shell Programming and Scripting
Hi...
i just want to write a script for the follwing command "display status" and the normal output is...
AN100> display status
12.13.2006 12:03:25 AN-2000-1 CC NOT PRESENT 16.50.80.49
status: Status for PACKET GLI A in the TOP / LEFT shelf of frame 0:
status: The current active LAN is... (5 Replies)
Discussion started by: gini
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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
output.
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
integer 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 [...].
Iteration 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 index variables from being 1-based (awk style) to 0-based (Perl style). Be sure to change all
operations the variable is involved in 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-1]. 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 v5.12.1 2010-04-26 A2P(1)