I'm using
while( (getline line < "filename") > 0 )
within my BEGIN statement, but this while loop only seems to read the last line of the file instead of each line. I think it may be a newline character problem, but really I don't know. Any ideas?
I'm trying to read the data in from a file other than the main input file.
The same syntax actually works for one file, but not another, and the only difference I see is that the one for which it DOES work has "^M" at the end of each line when I look at it in Vim, and the one for which it DOESN'T work doesn't have ^M. But this seems like an odd problem to be having on my (UNIX based) Mac.
I wish I understood what was going with getline a lot better than I do.
You would have to specify RS to something more vague.
Here is a ugly hack to get things working
RS="[\x0d\x0a\x0d]"
Now, this may require some explanation.
Diffrent systems use difrent ways to handle change of line.
Read http://en.wikipedia.org/wiki/Carriage_return and http://en.wikipedia.org/wiki/Newline if you are
interested in it.
Normally awk hadles this gracefully, but it appears that in your enviroment, some files are being naughty.
0x0d or 0x0a or 0x0d 0x0a (CR+LF) should be there, but not mixed.
So lets try a example of a mixed data stream
$ echo -e "foo\x0d\x0abar\x0d\x0adoe\x0arar\x0azoe\x0dqwe\x0dtry" |awk 'BEGIN{while((getline r )>0){print "r=["r"]";}}'
Result:
r=[foo]
r=[bar]
r=[doe]
r=[rar]
try]oe
We can see that the last lines are lost.
Now using the ugly hack to RS
$ echo -e "foo\x0d\x0abar\x0d\x0adoe\x0arar\x0azoe\x0dqwe\x0dtry" |awk 'BEGIN{RS="[\x0d\x0a\x0d]";while((getline r )>0){print "r=["r"]";}}'
Result:
r=[foo]
r=[bar]
r=[doe]
r=[rar]
r=[zoe]
r=[qwe]
r=[try]
We can see every line is obtained, reguardless of the 0x0d 0x0a junk :-)
Maybe you should preprocess your input file with for example dos2unix (http://sourceforge.net/projects/dos2unix/) utility?
Related
I have a file (an author list from the Library of Congress) with lines like:
Arteaga, Ana Mar�ia
Corval�an-V�asquez, Oscar E.
(when printed to linux console)
I'd like to read those (either into a pandas dataframe or a set of lines)
df = pd.read_csv(fname, sep='\t', header='infer', lineterminator=None,encoding='latin1') #lineterminator \r\n hits error
or
with open(fname,'r',encoding='ISO-8859-1') as fp:
lines=fp.readlines()
but both are not quite right , giving me output like
Arteaga, Ana Marâia
(again when printed to console)
when I am pretty sure the actual name here should be María.
Does someone recognize this format?
Ok this seems to be the 'marc-8' format .
yaz-iconv -f marc8 -t utf8 infile.txt > outfile.txt
took care of the conversion to utf8 , with the sole hiccup being that yaz killed all the line terminators (both for \r\n and \n versions of the file).
Those can be returned with something along the lines of
sed 's/\[/\n\[/g' outfile.txt > outfile_utf.txt
(for example in my case where each line starts with a '[' character)
when you scrutiny my questions from the past weeks you find I asked questions similar to this one. I had problems to ask in a demanded format since I did not really know where my problems came from. E. Morton tells me not to use range expression. Well, I do not know what they are excactly. I found in this forum many questions alike mine with working answers.
Like: "How to print following line from a match" (e.g.)
But all solutions I found stop working when I process more than one input file. I need to process many.
I use this command:
gawk -f 1.awk print*.csv > new.txt
while 1.awk contains:
BEGIN { OFS=FS=";"
pattern="row4"
}
go {print} $0 ~ pattern {go = 1}
input file 1 print1.csv contains:
row1;something;in;this;row;;;;;;;
row2;something;in;this;row;;;;;;;
row3;something;in;this;row;;;;;;;
row4;don't;need;to;match;the;whole;line,;
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
Input file 2 print2.csv contains the same just for illustration purpose.
The 1.awk (and several others ways I found in this forum to print from match) works for one file. Output:
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
BUT not when I process more input files.
Each time I process this way more than one input file awk commands 'to print from match' seem to be ignored.
As said I was told not to use range expression. I do not know how and maybe the problem is linked to the way I input several files?
just reset your match indicator at the beginning of each file
$ awk 'FNR==1{p=0} p; /row4/{p=1} ' file1 file2
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
row5;something;in;this;row;;;;;;;
row6;something;in;this;row;;;;;;;
row7;something;in;this;row;;;;;;;
row8;something;in;this;row;;;;;;;
row9;something;in;this;row;;;;;;;
row10;something;in;this;row;;;;;;;
UPDATE
From the comments
is it possible to combine your awk with: "If $1="row5" then write in
$6="row5" and delete the value "row5" in $5? In other words, to move
content "row5" in column1, if found there, to new column 6? I could to
this with another awk but a combination into one would be nicer
... $1=="row5"{$6=$5; $5=""} ...
or, if you want to use another field instead of $5 replace $5 with the corresponding field number.
We are currently using sed to filter output of regression runs. Sometimes we have a filter that looks like this:
/copyright/,/end copyright/d
If that end copyright is ever missing, the rest of the file is deleted. I'm wondering if there's some way to generate an error for this? awk would also be okay to use. I don't really want to add code that reads the file line by line and issues an error if it hits EOF.
here's a string
copyright
2016 jan 15
end copyright
date 2016 jan 5 time 15:36
last one
I'd like to get an error if end copyright is missing. The real filter also would replace the date line with DATE, so it's more that just ripping out the copyright.
You can persuade sed to generate an error if you reach end of input (i.e. see address $) between your start and end, but it won't be a very helpful message:
/copyright/,/end copyright/{
$s//\1/ # here
d
}
This will error if end copyright is missing or on the last line, with an exit status of 1 and the helpful message:
sed: -e expression #1, char 0: invalid reference \1 on `s' command's RHS
If you're using this in a makefile, you might want to echo a helpful message first, or (better) to wrap this in something that catches the error and produces a more useful one.
I tested this with GNU sed; though if you are using GNU sed, you could more easily use its useful extension:
q [EXIT-CODE]
This command only accepts a single address.
Exit 'sed' without processing any more commands or input. Note
that the current pattern space is printed if auto-print is not
disabled with the -n options. The ability to return an exit code
from the 'sed' script is a GNU 'sed' extension.
Q [EXIT-CODE]
This command only accepts a single address.
This command is the same as 'q', but will not print the contents of
pattern space. Like 'q', it provides the ability to return an exit
code to the caller.
So you could simply write
/copyright/,/end copyright/{
$Q 42
d
}
Never use range expressions /start/,/end/ as they make trivial code very slightly briefer but require a complete rewrite or duplicate conditions when you have the tiniest requirements change. Always use a flag instead. Note that since sed doesn't support variables, it doesn't support flag variables, and so you shouldn't be using sed you should be using awk instead.
In this case your original code would be:
awk '/copyright/{f=1} !f; /end copyright/{f=0}' file
And your modified code would be:
awk '/copyright/{f=1} !f; /end copyright/{f=0} END{if (f) print "Missing end copyright"}' file
The above is obviously untested since you didn't provide any sample input/output we could test a potential solution against.
With sed you can build a loop:
sed -e '/copyright/{:a;/end copyright/d;N;ba;};' file
:a defines the label "a"
/copyright end/d deletes the pattern space, only when "end copyright" matches
N appends the next line to the pattern space
ba jumps to the label "a"
Note that d ends the loop.
In this way you can avoid to delete the text until the end.
If you don't want the text to be displayed at all and prefer an error message when a "copyright" block stays unclosed, you obviously need to wait the end of the file. You can do it with sed too storing all the lines in the buffer space until the end:
sed -n -e '/copyright/{:a;/end copyright/d;${c\ERROR MESSAGE
;};N;ba;};H;${g;p};' file
H appends the current line to the buffer space
g put the content of the buffer space to the pattern space
The file content is only displayed once the last line reached with ${g;p} otherwise when the closing "end copyright" is missing, the current line is changed in the error message with ${c\ERROR MESSAGE\n;} inside the loop.
This way you can test what returns sed before redirecting it to whatever you want.
I have a problem with ksh in that a while loop is failing to obey the "while" condition. I should add now that this is ksh88 on my client's Solaris box. (That's a separate problem that can't be addressed in this forum. ;) I have seen Lance's question and some similar but none that I have found seem to address this. (Disclaimer: NO I haven't looked at every ksh question in this forum)
Here's a very cut down piece of code that replicates the problem:
1 #!/usr/bin/ksh
2 #
3 go=1
4 set -x
5 tail -0f loop-test.txt | while [[ $go -eq 1 ]]
6 do
7 read lbuff
8 set $lbuff
9 nwords=$#
10 printf "Line has %d words <%s>\n" $nwords "${lbuff}"
11 if [[ "${lbuff}" = "0" ]]
12 then
13 printf "Line consists of %s; time to absquatulate\n" $lbuff
14 go=0 # Violate the WHILE condition to get out of loop
15 fi
16 done
17 printf "\nLooks like I've fallen out of the loop\n"
18 exit 0
The way I test this is:
Run loop-test.sh in background mode
In a different window I run commands like "echo some nonsense >>loop_test.txt" (w/o the quotes, of course)
When I wish to exit, I type "echo 0 >>loop-test.txt"
What happens? It indeed sets go=0 and displays the line:
Line consists of 0; time to absquatulate
but does not exit the loop. To break out I append one more line to the txt file. The loop does NOT process that line and just falls out of the loop, issuing that "fallen out" message before exiting.
What's going on with this? I don't want to use "break" because in the actual script, the loop is monitoring the log of a database engine and the flag is set when it sees messages that the engine is shutting down. The actual script must still process those final lines before exiting.
Open to ideas, anyone?
Thanks much!
-- J.
OK, that flopped pretty quick. After reading a few other posts, I found an answer given by dogbane that sidesteps my entire pipe-to-while scheme. His is the second answer to a question (from 2013) where I see neeraj is using the same scheme I'm using.
What was wrong? The pipe-to-while has always worked for input that will end, like a file or a command with a distinct end to its output. However, from a tail command, there is no distinct EOF. Hence, the while-in-a-subshell doesn't know when to terminate.
Dogbane's solution: Don't use a pipe. Applying his logic to my situation, the basic loop is:
while read line
do
# put loop body here
done < <(tail -0f ${logfile})
No subshell, no problem.
Caveat about that syntax: There must be a space between the two < operators; otherwise it looks like a HEREIS document with bad syntax.
Er, one more catch: The syntax did not work in ksh, not even in the mksh (under cygwin) which emulates ksh93. But it did work in bash. So my boss is gonna have a good laugh at me, 'cause he knows I dislike bash.
So thanks MUCH, dogbane.
-- J
After articulating the problem and sleeping on it, the reason for the described behavior came to me: After setting go=0, the control flow of the loop still depends on another line of data coming in from STDIN via that pipe.
And now that I have realized the cause of the weirdness, I can speculate on an alternative way of reading from the stream. For the moment I am thinking of the following solution:
Open the input file as STDIN (Need to research the exec syntax for that)
When the condition occurs, close STDIN (Again, need to research the syntax for that)
It should then be safe to use the more intuitive:while read lbuffat the top of the loop.
I'll test this out today and post the result. I'd hope someone else benefit from the method (if it works).
I am new to DCL.
I want to get the out put of a command in a variable and iterate result one by one.
filePath=dir /since="time_now" [.SUBDIR]*.PNG/noheader/notrail
That's just not how we roll with DCL.
We don't do pipes, we do, but not really.
DIR/SINCE=NOW ... will not give anything by definition, since nothing exists since now.
Use /OUT to stick the directory output into a file, and then read ans parse (F$PARSE and/or F$ELEMENT and/or F$LOC)
Check out HELP OPEN; HELP READ [/END]; HELP LEXICAL
Google for examples.
More advanced DCL scripts use F$PARSE, F$SEARCH and F$FILE(file,CDT) to avoid activating images and creating temp files: $ HELP LEXICAL
Google for examples.
Check out yesterday stack-exhange entry ?! : OpenVMS - DELETE Line if TEXT like x
But if you are just starting... IMHO just skip DCL and stick to PERL
$ perl -e "for (<[.SUBDIR]*.PNG>) { next unless -M > 0.123; print; ... }"
Good luck!
Hein
top:
file = f$search("[.subdir]*.PNG")
if (file .eqs. "")then goto cont
mtime=f$file_attribute(file,"RDT")
if mtime.ges.build_start_time then -
name=f>parse(file,,,"NAME")
call CHECK "''name'"
goto top
cont:
#Hein please review this code and suggest changes