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Full Discussion: assigning variables in sed command
Top Forums Shell Programming and Scripting assigning variables in sed command Post 98013 by matrixmadhan on Saturday 4th of February 2006 11:15:57 AM
Old 02-04-2006
Quote:
Originally Posted by wxornot
I need to assign a variable within a variable in a sed command.
I tried doing the following in c shell.


set left = 1
set right = 2
set segment = qwerty

sed -n -e "/$segment{$left}/,/$segment{$right}/p" file.txt


what is wrong with this syntax?
sed goes by
sed 's/<searchtext>/<replacementtext>/' file

using variables within sed

a=abcdef
b=def
echo abcdefghij | sed "s/$b/$a/"
abcabcdefghij

hope this helps.
 

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LEARN ABOUT OSX

shmget

SHMGET(2)						      BSD System Calls Manual							 SHMGET(2)

NAME

     shmget -- get shared memory area identifier

SYNOPSIS

     #include <sys/shm.h>

     int
     shmget(key_t key, size_t size, int shmflg);

DESCRIPTION

     shmget() returns the shared memory identifier associated with the key key.

     A shared memory segment is created if either key is equal to IPC_PRIVATE, or key does not have a shared memory segment identifier associated
     with it, and the IPC_CREAT bit is set in shmflg.

     If a new shared memory segment is created, the data structure associated with it (the shmid_ds structure, see shmctl(2)) is initialized as
     follows:

     o	 shm_perm.cuid and shm_perm.uid are set to the effective uid of the calling process.

     o	 shm_perm.gid and shm_perm.cgid are set to the effective gid of the calling process.

     o	 shm_perm.mode is set to the lower 9 bits of shmflg.

     o	 shm_lpid, shm_nattch, shm_atime, and shm_dtime are set to 0

     o	 shm_ctime is set to the current time.

     o	 shm_segsz is set to the value of size.

     o	 The ftok(3) function may be used to generate a key from a pathname.

RETURN VALUES

     Upon successful completion a positive shared memory segment identifier is returned.  Otherwise, -1 is returned and the global variable errno
     is set to indicate the error.

ERRORS

     The shmget() system call will fail if:

     [EACCES]		A shared memory segment is already associated with key and the caller has no permission to access it.

     [EEXIST]		Both IPC_CREAT and IPC_EXCL are set in shmflg, and a shared memory segment is already associated with key.

     [EINVAL]		No shared memory segment is to be created, and a shared memory segment exists for key, but the size of the segment associ-
			ated with it is less than size, which is non-zero.

     [ENOENT]		IPC_CREAT was not set in shmflg and no shared memory segment associated with key was found.

     [ENOMEM]		There is not enough memory left to created a shared memory segment of the requested size.

     [ENOSPC]		A new shared memory identifier could not be created because the system limit for the number of shared memory identifiers
			has been reached.

LEGACY SYNOPSIS

     #include <sys/types.h>
     #include <sys/ipc.h>
     #include <sys/shm.h>

     int
     shmget(key_t key, int size, int shmflg);

     All of these include files are necessary.	The type of size has changed.

SEE ALSO

     ftok(3), shmat(2), shmctl(2), shmdt(2), compat(5)

BSD
								  August 17, 1995							       BSD
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