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 DEBIAN
filter_create_fd
filter_create_fd(3) util/filter.h filter_create_fd(3)NAME
filter_create_fd - Create a sub process and return the requested pipes
SYNOPSIS
#include <util/filter.h>
NEOERR *filter_create_fd(const char *cmd, int *fdin, int *fdout, int *fderr,
pid_t *pid);
ARGUMENTS
cmd -> the sub command to execute. Will be executed with
/bin/sh -c
fdin -> pointer to return the stdin pipe, or NULL if you don't
want the stdin pipe
fdout -> pointer to return the stdout pipe, or NULL if you don't
want the stdout pipe
fderr -> pointer to return the stderr pipe, or NULL if you don't
want the stderr pipe
DESCRIPTION
filter_create_fd and filter_create_fp are what popen
been: a mechanism to create sub processes and have pipes to all their input/output. The concept was taken from mutt, though python has
something similar with popen3/popen4. You control which pipes the function returns by the fdin/fdout/fderr arguments. A NULL value means
"don't create a pipe", a pointer to an int will cause the pipes to be created and the value of the file descriptor stored in the int. You
will have to close(2) the file descriptors yourself.
RETURN VALUE
fdin -> the stdin file descriptor of the sub process
fdout -> the stdout file descriptor of the sub process
fderr -> the stderr file descriptor of the sub process
pid -> the pid of the sub process
SEE ALSO filter_wait(3), filter_create_fp(3), filter_create_fd
ClearSilver 12 July 2007 filter_create_fd(3)