I have this line about 500 times in a my file backup.xml
my-company-review/</link>
Is there a way through command line, perl, etc. to add a number into the line after the word review. For example, something like this:
my-company-review1/</link>
my-company-review2/</link>
my-company-review3/</link>
Thanks in advance for the help!
Why not use Perl, as I suggested with your last problem. Once again, this is a sort of hack solution, that only works if there's a maximum of one replacement per line... But it's a quick throw-away program.
perl -e '$count=1; foreach (<>) { s/(my-company-review)(\/<\/link>)/$1$count$2/ && $count++; print; }'
An extra loop will do multiple substitutions on a line:
perl -e '$count=1; foreach (<>) { while(s/(my-company-review)(\/<\/link>)/$1$count$2/) {$count++;} print; }'
That awk solution looks way nicer =)
Here's one way:
perl -i -wpe ' BEGIN { $count = 1; }
++$count
if s{(my-company-review)(/</link>)}{$1$count$2};
' backup.xml
(Disclaimer: not tested.)
You can use awk:
awk 'gsub("/</link>", NR "/</link>")' infile
or perl:
perl -ne 's:/</link>:$./</link>:; print' infile
Related
I have a file test.txt that reads as follows:
one
two
three
Now, I want to print each line of this file as follows:
.one (one)
.two (two)
.three (three)
I try this in Perl:
#ARGV = ("test.txt");
while (<>) {
print (".$_ \($_\)");
}
This doesn't seem to work and this is what I get:
.one
(one
).two
(two
).three
(three
)
Can some help me figure out what's going wrong?
Update :
Thanks to Aureliano Guedes for the suggestion.
This 1-liner seems to work :
perl -pe 's/([^\s]+)/.$1 ($1)/'
$_ will include the newline, e.g. one\n, so print ".$_ \($_\)" becomes something like print ".one\n (one\n).
Use chomp to get rid of them, or use s/\s+\z// to remove all trailing whitespace.
while (<>) {
chomp;
print ".$_ ($_)\n";
}
(But add a \n to print the newline that you do want.)
Besides the correct answer already given, you can do this in a oneliner:
perl -pe 's/(.+)/.$1 ($1)/'
Or if you prefer a while loop:
while (<>) {
s/(.+)/.$1 ($1)/;
print;
}
This simply modifies your current line to your desired output and prints it then.
Another Perl one-liner without using regex.
perl -ple ' $_=".$_ ($_)" '
with the given inputs
$ cat test.txt
one
two
three
$ perl -ple ' $_=".$_ ($_)" ' test.txt
.one (one)
.two (two)
.three (three)
$
I'm writing a Perl script to read a log so that to re-write the file into a new log by removing empty lines in case of seeing any consecutive blank lines of 4 or more. In other words, I'll have to compress any 4 consecutive blank lines (or more lines) into one single line; but any case of 1, 2 or 3 lines in the file will have to remain the format. I have tried to get the solution online but the only I can find is
perl -00 -pe ''
or
perl -00pe0
Also, I see the example in vim like this to delete blocks of 4 empty lines :%s/^\n\{4}// which match what I'm looking for but it was in vim not Perl. Can anyone help in this? Thanks.
To collapse 4+ consecutive Unix-style EOLs to a single newline:
$ perl -0777 -pi.bak -e 's|\n{4,}|\n|g' file.txt
An alternative flavor using look-behind:
$ perl -0777 -pi.bak -e 's|(?<=\n)\n{3,}||g' file.txt
use strict;
use warnings;
my $cnt = 0;
sub flush_ws {
$cnt = 1 if ($cnt >= 4);
while ($cnt > 0) {print "\n"; $cnt--; }
}
while (<>) {
if (/^$/) {
$cnt++;
} else {
flush_ws();
print $_;
}
}
flush_ws();
Your -0 hint is a good one since you can use -0777 to slurp the whole file in -p mode. Read more about these guys in perlrun So this oneliner should do the trick:
$ perl -0777 -pe 's/\n{5,}/\n\n/g'
If there are up to four new lines in a row, nothing happens. Five newlines or more (four empty lines or more) are replaced by two newlines (one empty line). Note the /g switch here to replace not only the first match.
Deparsed code:
BEGIN { $/ = undef; $\ = undef; }
LINE: while (defined($_ = <ARGV>)) {
s/\n{5,}/\n\n/g;
}
continue {
die "-p destination: $!\n" unless print $_;
}
HTH! :)
One way using GNU awk, setting the record separator to NUL:
awk 'BEGIN { RS="\0" } { gsub(/\n{5,}/,"\n")}1' file.txt
This assumes that you're definition of empty excludes whitespace
This will do what you need
perl -ne 'if (/\S/) {$n = 1 if $n >= 4; print "\n" x $n, $_; $n = 0} else {$n++}' myfile
Ok I guess I need something that will do the following:
search for this line of code in /var/lib/asterisk/bin/retrieve_conf:
$engineinfo = engine_getinfo();
insert these two lines immediately following:
$engineinfo['engine']="asterisk";
$engineinfo['version']="1.6.2.11";
Thanks in advance,
Joe
You could do it like this
sed -ne '/$engineinfo = engine_getinfo();/a\'$'\n''$engineinfo['engine']="asterisk";\'$'\n''$engineinfo['version']="1.6.2.11";'$'\n'';p' /var/lib/asterisk/bin/retrieve_conf
Add -i for modification in place once you confirm that it works.
What does it do and how does it work?
First we tell sed to match a line containing your string. On that matched line we then will perform an a command, which is "append text".
The syntax of a sed a command is
a\
line of text\
another line
;
Note that the literal newlines are part of this syntax. To make it all one line (and preserve copy-paste ability) in place of literal newlines I used $'\n' which will tell bash or zsh to insert a real newline in place. The quoting necessary to make this work is a little complex: You have to exit single-quotes so that you can have the $'\n' be interpreted by bash, then you have to re-enter a single-quoted string to prevent bash from interpreting the rest of your input.
EDIT: Updated to append both lines in one append command.
You can use Perl and Tie::File (included in the Perl distribution):
use Tie::File;
tie my #array, 'Tie::File', "/var/lib/asterisk/bin/retrieve_conf" or die $!;
for (0..$#array) {
if ($array[$_] =~ /\$engineinfo = engine_getinfo\(\);/) {
splice #array, $_+1, 0, q{$engineinfo['engine']="asterisk"; $engineinfo['version']="1.6.2.11";};
last;
}
}
Just for the sake of symmetry here's an answer using awk.
awk '{ if(/\$engineinfo = engine_getinfo\(\);/) print $0"\n$engineinfo['\''engine'\'']=\"asterisk\";\n$engineinfo['\''version'\'']=\"1.6.2.11\"" ; else print $0 }' in.txt
You may also use ed:
# cf. http://wiki.bash-hackers.org/howto/edit-ed
cat <<-'EOF' | ed -s /var/lib/asterisk/bin/retrieve_conf
H
/\$engineinfo = engine_getinfo();/a
$engineinfo['engine']="asterisk";
$engineinfo['version']="1.6.2.11";
.
wq
EOF
A Perl one-liner:
perl -pE 's|(\$engineinfo) = engine_getinfo\(\);.*\K|\n${1}['\''engine'\'']="asterisk";\n${1}['\''version'\'']="1.6.2.11";|' file
sed -i 's/$engineinfo = engine_getinfo();/$engineinfo = engine_getinfo();<CTRL V><CNTRL M>$engineinfo['engine']="asterisk"; $engineinfo['version']="1.6.2.11";/' /var/lib/asterisk/bin/retrieve_conf
In awk I can write: awk -F: 'BEGIN {OFS = FS} ...'
In Perl, what's the equivalent of FS? I'd like to write
perl -F: -lane 'BEGIN {$, = [what?]} ...'
update with an example:
echo a:b:c:d | awk -F: 'BEGIN {OFS = FS} {$2 = 42; print}'
echo a:b:c:d | perl -F: -ane 'BEGIN {$, = ":"} $F[1] = 42; print #F'
Both output a:42:c:d
I would prefer not to hard-code the : in the Perl BEGIN block, but refer to wherever the -F option saves its argument.
To sum up, what I'm looking for does not exist:
there's no variable that holds the argument for -F, and more importantly
Perl's "FS" is fundamentally a different data type (regular expression) than the "OFS" (string) -- it does not make sense to join a list of strings using a regex.
Note that the same holds true in awk: FS is a string but acts as regex:
echo a:b,c:d | awk -F'[:,]' 'BEGIN {OFS=FS} {$2=42; print}'
outputs "a[:,]42[:,]c[:,]d"
Thanks for the insight and workarounds though.
You can use perl's -s (similar to awk's -v) to pass a "FS" variable, but the split becomes manual:
echo a:b:c:d | perl -sne '
BEGIN {$, = $FS}
#F = split $FS;
$F[1] = 42;
print #F;
' -- -FS=":"
If you know the exact length of input, you could do this:
echo a:b:c:d | perl -F'(:)' -ane '$, = $F[1]; #F = #F[0,2,4,6]; $F[1] = 42; print #F'
If the input is of variable lengths, you'll need something more sophisticated than #f[0,2,4,6].
EDIT: -F seems to simply provide input to an automatic split() call, which takes a complete RE as an expression. You may be able to find something more suitable by reading the perldoc entries for split, perlre, and perlvar.
You can sort of cheat it, because perl is actually using the split function with your -F argument, and you can tell split to preserve what it splits on by including capturing parens in the regex:
$ echo a:b:c:d | perl -F'(:)' -ane 'print join("/", #F);'
a/:/b/:/c/:/d
You can see what perl's doing with some of these "magic" command-line arguments by using -MO=Deparse, like this:
$ perl -MO=Deparse -F'(:)' -ane 'print join("/", #F);'
LINE: while (defined($_ = <ARGV>)) {
our(#F) = split(/(:)/, $_, 0);
print join('/', #F);
}
-e syntax OK
You'd have to change your #F subscripts to double what they'd normally be ($F[2] = 42).
Darnit...
The best I can do is:
echo a:b:c:d | perl -ne '$v=":";#F = split("$v"); $F[1] = 42; print join("$v", #F) . "\n";'
You don't need the -F: this way, and you're only stating the colon once. I was hoping there was someway of setting variables on the command line like you can with Awk's -v switch.
For one liners, Perl is usually not as clean as Awk, but I remember using Awk before I knew of Perl and writing 1000+ line Awk scripts.
Trying things like this made people think Awk was either named after the sound someone made when they tried to decipher such a script, or stood for AWKward.
There is no input record separator in Perl. You're basically emulating awk by using the -a and -F flags. If you really don't want to hard code the value, then why not just use an environmental variable?
$ export SPLIT=":"
$ perl -F$SPLIT -lane 'BEGIN { $, = $ENV{SPLIT}; } ...'
I have a text file which contains:
Cycle code
Cycle month
Cycle year
Event type ID
Event ID
Network start time
I want to change this text so that when ever there is a space, I want to replace it with a _. And after that, I want the characters to lower case letter like below:
cycle_code
cycle_month
cycle_year
event_type_id
event_id
network_start_time
How could I accomplish this?
Another Perl method:
perl -pe 'y/A-Z /a-z_/' file
tr alone works:
tr ' [:upper:]' '_[:lower:]' < file
Looking into sed documentation some more and following advice from the comments the following command should work.
sed -r {filehere} -e 's/[A-Z]/\L&/g;s/ /_/g' -i
There is a perl tag in your question as well. So:
#!/usr/bin/perl
use strict; use warnings;
while (<DATA>) {
print join('_', split ' ', lc), "\n";
}
__DATA__
Cycle code
Cycle month
Cycle year
Event type ID
Event ID
Network start time
Or:
perl -i.bak -wple '$_ = join('_', split ' ', lc)' test.txt
sed "y/ABCDEFGHIJKLMNOPQRSTUVWXYZ /abcdefghijklmnopqrstuvwxyz_/" filename
Just use your shell, if you have Bash 4
while read -r line
do
line=${line,,} #change to lowercase
echo ${line// /_}
done < "file" > newfile
mv newfile file
With gawk:
awk '{$0=tolower($0);$1=$1}1' OFS="_" file
With Perl:
perl -ne 's/ +/_/g;print lc' file
With Python:
>>> f=open("file")
>>> for line in f:
... print '_'.join(line.split()).lower()
>>> f.close()