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Full Discussion: understanding sed command
Top Forums UNIX for Dummies Questions & Answers understanding sed command Post 302572510 by forroughuse on Thursday 10th of November 2011 07:48:07 AM
Old 11-10-2011
understanding sed command

Hi Friends,

I need a small help in understanding the below sed command.
Code:
$ cat t4.txt
     1 root       1  58    0  888K  368K sleep    4:06  0.00% init
     1 root       1  58    0  888K  368K sleep    4:06  0.00% init  last

 
$ sed 's/[ ][^ ]*$//' t4.txt
     1 root       1  58    0  888K  368K sleep    4:06  0.00%
     1 root       1  58    0  888K  368K sleep    4:06  0.00% init

I am unable to understand how "sed 's/[ ][^ ]*$//' " is removing last character of each line.

Can someone please explain me.

Thanks in advance

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Last edited by vbe; 11-10-2011 at 08:56 AM..
 

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SWITCH_ROOT(8)						       System Administration						    SWITCH_ROOT(8)

NAME
switch_root - switch to another filesystem as the root of the mount tree SYNOPSIS
switch_root [-hV] switch_root newroot init [arg...] DESCRIPTION
switch_root moves already mounted /proc, /dev, /sys and /run to newroot and makes newroot the new root filesystem and starts init process. WARNING: switch_root removes recursively all files and directories on the current root filesystem. OPTIONS
-h, --help Display help text and exit. -V, --version Display version information and exit. RETURN VALUE
switch_root returns 0 on success and 1 on failure. NOTES
switch_root will fail to function if newroot is not the root of a mount. If you want to switch root into a directory that does not meet this requirement then you can first use a bind-mounting trick to turn any directory into a mount point: mount --bind $DIR $DIR SEE ALSO
chroot(2), init(8), mkinitrd(8), mount(8) AUTHORS
Peter Jones <pjones@redhat.com> Jeremy Katz <katzj@redhat.com> Karel Zak <kzak@redhat.com> AVAILABILITY
The switch_root command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/. util-linux June 2009 SWITCH_ROOT(8)
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