I like pipes. One command produces a list into a pipe, the next modified that list, and so on down the pipe. A shell subscript can be on the pipe, like " | while read x y z ;do . . . done | ". Variables are nice to catch one field of one line, or the output of one command, for testing and output. You can process lists using the comm command, which takes sorted files or pipelines and tells you which lines are in file a, only, which in file b only, and which in both files. In bash and some systems' ksh, this drops a name of a pipe from a sort " <( sort file1 ) ". So, this produces a list of lines new in file b and passes it to a subshell loop for processing, one line $l at a time:
Code:
comm -13 <( sort filea ) <( sort fileb ) | while read l
do
...
done
Hi ,
Assume today's date is 10-May-2002. I want to get a list of files which were last modified since 01-May-2002. If I run the script after 5 days, it should still list me the files modified from 01-May-2002 till today. I also plan to pass the date 01-May-2002 as an argument to the shell script... (3 Replies)
i would be grateful if someone could supply me with a shell script which performed a ftp but only retrieved files which had a created date greater than a specific date - is this possible with ftp?
many thanks
mc (1 Reply)
Hi,
Wondering if anyone could help me with a simple script to filter out multiple things from a file.
Right now I just have long lines of grep -v remove file | greg -v etc etc
What I would like to do is have grep -v <run everything in a file> tofilter
If that makes sense. Basically a... (2 Replies)
Hi
I need to find the list of files in a directory and to do some specific operations based on the type of files.
suppose in a directory am having .dat , .log, .err, .rej file types. i need to filter out .dat and .log only which are older than six months.
i used the below query but the... (2 Replies)
Hi
My OS is solaris 64 bit 10, I have many files in a logs directory where we recive 40-50 logs every day. i have last 20 days file present in this directory. I want to move each day file to a particulaar directory whose name is appended with the date of file.
eg
Code:
1.txt file... (1 Reply)
Dear All,
I am capturing system date and creating the file by using that time stamp, file is getting appended with checks of application & database check logs.
But when the date is in between 1 to 9 both inclusive, it appends a single space to file name but after 9th it works fine.
... (5 Replies)
Hi,
I've no problems filtering text in awk but whenever I try to filter date format such as 03022013, I couldn't get awk to filter the item out.
Any tips? (8 Replies)
Hi,
Could you please provide me command to filter contents between date in a log file?
Say for example, in a log file I want to capture contents between date May 01 from 5am to 9 am.
OS -- Linux
Regards,
Maddy (1 Reply)
Discussion started by: Maddy123
1 Replies
LEARN ABOUT MOJAVE
pipe
PIPE(2) BSD System Calls Manual PIPE(2)NAME
pipe -- create descriptor pair for interprocess communication
SYNOPSIS
#include <unistd.h>
int
pipe(int fildes[2]);
DESCRIPTION
The pipe() function creates a pipe (an object that allows unidirectional data flow) and allocates a pair of file descriptors. The first
descriptor connects to the read end of the pipe; the second connects to the write end.
Data written to fildes[1] appears on (i.e., can be read from) fildes[0]. This allows the output of one program to be sent to another pro-
gram: the source's standard output is set up to be the write end of the pipe; the sink's standard input is set up to be the read end of the
pipe. The pipe itself persists until all of its associated descriptors are closed.
A pipe whose read or write end has been closed is considered widowed. Writing on such a pipe causes the writing process to receive a SIGPIPE
signal. Widowing a pipe is the only way to deliver end-of-file to a reader: after the reader consumes any buffered data, reading a widowed
pipe returns a zero count.
The generation of the SIGPIPE signal can be suppressed using the F_SETNOSIGPIPE fcntl command.
RETURN VALUES
On successful creation of the pipe, zero is returned. Otherwise, a value of -1 is returned and the variable errno set to indicate the error.
ERRORS
The pipe() call will fail if:
[EFAULT] The fildes buffer is in an invalid area of the process's address space.
[EMFILE] Too many descriptors are active.
[ENFILE] The system file table is full.
SEE ALSO sh(1), fork(2), read(2), socketpair(2), fcntl(2), write(2)HISTORY
A pipe() function call appeared in Version 6 AT&T UNIX.
4th Berkeley Distribution February 17, 2011 4th Berkeley Distribution