[SOLVED] Regular Expression Anchor '$' Not Working In grep..

[gdawg]

Hi,
When I run

Code: Select all

jane@localhost ~> grep -h '.zip' dirlist*.txt
gunzip*
gzip*
bunzip2@
bzip2*
bzip2recover*
funzip*
gpg-zip*
gunzip@
gzip@
hunzip*
hzip*
mzip@
unzip*
unzipsfx*


However, I get this when I run:jane@localhost ~> grep -h 'zip$' dirlist*.txt I get no output. When I use '^' as an anchor I get the expected results. Is there a program that I need to install to be able to use '$' as an anchor? All help will be appreciated.
jane@localhost ~> uname -a
Linux localhost 2.6.38.8-desktop586-8.mga #1 SMP Fri Nov 4 00:11:45 UTC 2011 i686 i686 i386 GNU/Linux
I'm running Dell Inspiron 530S Desktop with Win 7 and numerous Linux distributions installed on two drives.

[doktor5000]

Well, from looking at the expression, zip$ matches "zip" at the end of a line, but in your case there's always a character behind the "zip", either * or @. So no match.

Would you mind to tell what you want to achieve in the first place, i.e. a bit more context information?

[gdawg]

Thank you for your reply doktor5000. The dirlist*.txt is constructed from a combination of /bin, /usr/bin, /sbin, and /usr/sbin. It is a representation of the following commands: ls /bin > dirlist-bin.txt; ls /usr/bin > dirlist-usr-bin.txt; ls /sbin > dirlist-sbin.txt; and ls /usr/sbin > dirlist-usr-sbin.txt. I'm studying The Linux Command Line and this is one of the exercises. As you have correctly pointed out, each "zip" is followed by a * or @ symbol. My question now becomes: why is that the case? A review of the various /bins' reveals that all files in those directories have trailing characters. Thank you for your assistance.

[doktor5000]

I'm studying The Linux Command Line and this is one of the exercises. As you have correctly pointed out, each "zip" is followed by a * or @ symbol. My question now becomes: why is that the case? A review of the various /bins' reveals that all files in those directories have trailing characters.

That depends on what options you supply to the ls command. An asterisk (*) symbolizes the executable permission, and an @ symbol symbolizes a symlink (short for symbolic link, also known as softlink) Just look at the manpage of the ls command, via man ls. The option -F is responsible for that behaviour, and there's a default alias for the ls command, see:

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[doktor5000@mageia1 ~]$ alias ls
alias ls='ls -F --color=auto'

So if you don't want that -F option you either need to unalias the ls command or call it with the full path:
Just compare the output of
/bin/ls /bin
and
ls /bin
If you need further explanations just say so

[gdawg]

Thank you doktor5000 for that excellent explanation. Where are the aliases set and how can I edit them? I looked in '.bashrc' and that alias wasn't listed and 'man ls' returns 'no manual entry for ls'.

[alf]

Where are the aliases set and how can I edit them?

aliases are defined in /etc/profile.d/xxalias.sh(where xx is a two digit number), don't know which it is in mageia exactly as I'm currently not in front of a mageia PC.
To list them all type 'alias' in console.

Oh, and before I forget to say, it's not a good idea to edit systemwide aliases as they could be overwritten by an update. Your own aliases will be stored in ~\.alias and used then instead of system aliases.

[doktor5000]

Oh, and before I forget to say, it's not a good idea to edit systemwide aliases as they could be overwritten by an update. Your own aliases will be stored in ~\.alias and used then instead of system aliases.

Actually you can also define them in ~/.bashrc, or anything that is source'd when you open up a shell

[gdawg]

Thank you very much alf and doktor5000. I found some aliases in /etc/profile.d/60alias.sh. I chose to leave those as-is and edited .bashrc to add alias ls='ls --color=auto. Thanks again for your excellent assistance.

Please mark this subject as solved. I can't seem to get it done.

[critter]

It is not necessary to permanently change an alias. If you want to execute the command bypassing the alias simply precede it with a backslash.
\ls instead of ls.

hth
critter

[gdawg]

Thank you critter for your help. I wasn't aware of that.

[ahtisham454]

Very informational and educational as usual!