Originally Posted by RudiC Does it? I don't think so. The | char opens a pipe and makes the shell wait for the next command in the pipe.
The shell command parsing step which looks for pipes has already concluded by the time parameter expansion occurs. There's nothing special about a pipe character in a variable. You'd have to use eval to make it so.
The command that was given in post#1 was
Executing this on the two systems I have at hand (Linux, FreeBSD) issues the secondary prompt (asking for the next command in pipe, I assume). The variable aa is not assigned to, it is not even defined afterwards. So I think my statement holds.
Of course, assigning an escaped | is totally different and absolutely OK.
I'm having some peculiar performance issues with my Gigabit Lan.
I have some 100Mb devices so I can't do the necessary "jumbo Frame" tweaks for absolute optimum performance as I'd prevent them access.
I'm getting appauling transfer rates sending files to the linux machine, around 10 Mbps 3%... (0 Replies)
Whenever I sftped a particular gzipped file to a particular directory and then try to unzip it, I get Permission Denied error.
With this file even I cannot do chmod. though the file permissions are -rw-r--r--
When same file I sftp to a different location I am able to gunzip it.
Directory... (0 Replies)
Hi all,
Ok os heres my situation. I have created a database style program that stores a persons info (name,address,phone number etc.) in a file ("database"). after i read in all the values above, i assign them to a line variable:
line="$name^$address^$phonenum" >> phonebuk
as you can see... (1 Reply)
Hi!
I am working in korn shell. I want to reset the dimiliter for the set command to "|" but instead of a command prompt return I am getting something as below
After issuing the command I am getting this....as if the shell is expecting something else. Can anybody suggest what's the problem.
... (2 Replies)
Scenario:
Step 1. I'm logging into AIX server using user id called user1
Step 2. I'm traversing to home directory of user2
Note: This user2's home directory has the permissions drwxr-s---
Step 3. I'm issuing command pwd there. I'm getting the expected output.
Step 4. I'm issuing the... (3 Replies)
hi I keep getting an error with this nested if statement and am getting the error unexpected end of file, can anyone help me as to why this wont execute?
#!/bin/bash
#script to check wether the -i -v statements run correctly
removeFile ()
{
mv $1 $HOME/deleted
}... (3 Replies)
I am using bash and resetting IFS as below when reading the command line arguments. I do this so I can call my script as in Ex1.
Ex1: ./synt2d-ray3dmod.bash --xsrc=12/20/30
This allows me to split both sides so that when I do "shift"
I can get 12/20/30
What I do not understand is... (21 Replies)
Hi ,
i am in my initial learning phase of unix. i was going thru the function part.
below is the example which was there but i am not able to understand logic and the use of IFS(internal field separator)
lspath() {
OLDIFS="$IFS"
IFS=:
for DIR in $PATH ; do echo $DIR ; done
IFS="$OLDIFS"... (8 Replies)
Discussion started by: scriptor
8 Replies
LEARN ABOUT HPUX
pipe
pipe(2) System Calls Manual pipe(2)NAME
pipe() - create an interprocess channel
SYNOPSIS DESCRIPTION
creates an I/O mechanism called a pipe and returns two file descriptors, fildes[0] and fildes[1]. fildes[0] is opened for reading and
fildes[1] is opened for writing.
A read-only file descriptor fildes[0] accesses the data written to fildes[1] on a first-in-first-out (FIFO) basis. For details of the I/O
behavior of pipes see read(2) and write(2).
By default, HP-UX pipes are not STREAMS-based. It is possible to generate the kernel so that all pipes created on a system are STREAMS-
based. This can only be done for HP-UX releases 10.0 and later. STREAMS-based FIFOs (created by or are not supported on HP-UX.
To generate a kernel that supports STREAMS-based pipes:
o STREAMS/UX must be installed.
o The module and the driver must be included in the file. (When STREAMS/UX is installed, and are automatically added to the system
file.)
o The tunable parameter (see streampipes(5)) must be set to 1 in the file. (This is not automatically done when STREAMS/UX is
installed.)
o The kernel must be generated and the system rebooted. Once this is done, all pipes created by will be STREAMS-based.
For more information, see
EXAMPLES
The following example uses to implement the command string
RETURN VALUE
returns one of the following values:
Successful completion.
Failure.
is set to indicate the error.
ERRORS
sets to one of the following error values if the corresponding condition is true.
or more file descriptors are currently open.
The system file table is full.
The file system lacks sufficient space to create the pipe.
Could not allocate resources for both Stream heads
(STREAMS-based pipes only).
SEE ALSO sh(1), read(2), write(2), popen(3S), privileges(5), streampipes(5), streamio(7).
STANDARDS CONFORMANCE pipe(2)