A file handle is an abstract indicator for accessing a file. It is retrieved after successfully opening the file using the file name. Afterwards the file handle is used instead of the file name for all file operations.
Questions tagged [filehandle]
388 questions
385
votes
4 answers
Does reading an entire file leave the file handle open?
If you read an entire file with content = open('Path/to/file', 'r').read() is the file handle left open until the script exits? Is there a more concise method to read a whole file?
tMC
- 15,585
- 10
- 57
- 95
42
votes
6 answers
Open in Java(TM) Platform SE binary
I tried to delete a file that I have two of, one slightly changed, so I could delete the older one and replace it with the new one I changed. When I tried to delete the file I got the error message 'file in use' where it said the action can't be…
user1642596
- 421
- 1
- 4
- 3
34
votes
3 answers
How can I use __DATA__ twice?
How can I use __DATA__ twice?
#!/usr/local/bin/perl
use warnings;
use 5.012;
while ( ) {
print;
}
while ( ) {
chomp if $. == 1;
print scalar reverse;
print "\n" if eof;
}
__DATA__
one
two
three
four
five
six
sid_com
- 21,289
- 23
- 89
- 171
33
votes
5 answers
How can I check if a filehandle is open in Perl?
Is there a way to check if a file is already open in Perl?
I want to have a read file access, so don't require flock.
open(FH, "<$fileName") or die "$!\n" if ();
# or something like
close(FH) if ();
matt
23
votes
1 answer
Where does Ruby keep track of its open file descriptors?
What This Question Is Not About
This question is not about how to auto-close a file with File#close or the File#open block syntax. It's a question about where Ruby stores its list of open file descriptors at runtime.
The Actual Question
If you have…
Todd A. Jacobs
- 71,673
- 14
- 128
- 179
21
votes
8 answers
Why does Image.FromFile keep a file handle open sometimes?
I am doing a lot of image processing in GDI+ in .NET in an ASP.NET application.
I frequently find that Image.FromFile() is keeping a file handle open.
Why is this? What is the best way to open an image without the file handle being retained.
NB:…
Simon_Weaver
- 120,240
- 73
- 577
- 618
21
votes
3 answers
Can I find a filename from a filehandle in Perl?
open(my $fh, '>', $path) || die $!;
my_sub($fh);
Can my_sub() somehow extrapolate $path from $fh?
sh-beta
- 3,319
- 4
- 25
- 32
19
votes
4 answers
Closing all open files in a process
How do I find all the open files in a process (from inside itself)?
This seems useful to know after a fork() (before exec()).
I know of the existance of getdtablesize() and the more portable sysconf(_SC_OPEN_MAX), but it seems inefficient to attempt…
Magnus
- 4,444
- 1
- 30
- 47
18
votes
3 answers
Perl - while (<>) file handling
A simple program with while( <> ) handles files given as arguments (./program 1.file 2.file 3.file) and standard input of Unix systems.
I think it concatenates them together in one file and work is line by line. The problem is, how do I know that…
Mantas Marcinkus
- 563
- 2
- 5
- 11
17
votes
2 answers
Re-reading from already read filehandle
I opened a file to read from line by line:
open(FH,"<","$myfile") or die "could not open $myfile: $!";
while ()
{
# ...do something
}
Later on in the program, I try to re-read the file (walk thru the file again):
while ()
{
# ...do…
rajeev
- 967
- 5
- 19
- 38
16
votes
4 answers
What's the Pythonic way to store a data block in a Python script?
Perl allows me to use the __DATA__ token in a script to mark the start of a data block. I can read the data using the DATA filehandle. What's the Pythonic way to store a data block in a script?
Charlie Guo
- 171
- 1
- 7
16
votes
2 answers
What is the preferred cross-platform IPC Perl module?
I want to create a simple IO object that represents a pipe opened to another program to that I can periodically write to another program's STDIN as my app runs. I want it to be bullet-proof (in that it catches all errors) and cross-platform. The…
theory
- 8,210
- 8
- 50
- 115
15
votes
3 answers
Read file into variable in Perl
Possible Duplicate:
What is the best way to slurp a file into a string in Perl?
Is this code a good way to read the contents of a file into a variable in Perl? It works, but I'm curious if there is a better practice I should be using.
open INPUT,…
itzy
- 9,217
- 13
- 48
- 88
15
votes
1 answer
Is there are Python equivalent of Perl's __DATA__ filehandle?
In Perl I often read data in from the filehandle __DATA__ at the end of the script:
while () {
chomp;
say;
}
__DATA__
line1
line2
I find this quicker for testing code etc than reading in a file, as it means I can edit its contents on…
fugu
- 5,941
- 4
- 29
- 67
14
votes
3 answers
Delphi - finding the process that is accessing a file from my program
I have a Delphi app that regularly writes to a local disk file. Occasionally it is unable to access the file - a sharing violation results when it tries to open it. A retry after a short delay is all that is needed, but when it occurs, I would…
rossmcm
- 5,184
- 7
- 51
- 108