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Prowler

Member

Registered: 2011-05-16

Posts: 16

Replacing text between backslashes

Hi, recently ive been working on a file backup script of mine (sorry if I am missing on an easier way for that). I have a list of files in an array:
gg[1]='/home/discharge/.bashrc'

I want to make a variable that takes gg[1] and removes everything until the name of the file itself is left. So what I need is

gg[1]='/home/discharge/.bashrc'
shorter[1]='.bashrc'

How to automate so that i can extract only that last part? Tried "sed", but after an hour of trying, I'm giving up on that.
Any ideas appreciated

skanky

Member

From: WAIS

Registered: 2009-10-23

Posts: 1,847

Re: Replacing text between backslashes

$basename /home/discharge/.bashrc
.bashrc

 $sed 's,/.*/,,' <<< '/home/discharge/.bashrc'
.bashrc

Edit, alphaniner's solution is probably best though. I keep forgetting about pe.

Last edited by skanky (2012-03-05 20:31:27)

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alphaniner

Member

From: Ancapistan

Registered: 2010-07-12

Posts: 2,810

Re: Replacing text between backslashes

Use bash parameter expansion for that!

${parameter##pattern}

so

if ${gg[1]} is '/home/discharge/.bashrc'
then ${gg[1]##*/} would be '.bashrc'

See Greg's Wiki for a proper explanation.  As an avid scripter, the Bash Guide at Greg's Wiki was the single best resource I ever read.

Last edited by alphaniner (2012-03-05 20:28:42)

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jasonwryan

Anarchist

From: .nz

Registered: 2009-05-09

Posts: 30,426

Website

Re: Replacing text between backslashes

Or, in bash with pe:

 echo "${gg[1]##*/}"
.bashrc

# waaay too slow...

Last edited by jasonwryan (2012-03-05 20:30:27)

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Prowler

Member

Registered: 2011-05-16

Posts: 16

Re: Replacing text between backslashes

$basename /home/discharge/.bashrc
.bashrc

 $sed 's,/.*/,,' <<< '/home/discharge/.bashrc'
.bashrc

Edit, alphaniner's solution is probably best though. I keep forgetting about pe.

I didn't even suspect there was a bash script lying around just for that purpose! Of the three that is the simplest to use. And thanks for the sed one, it was chopping my mind how i couldnt get it working - started building from an old sed syntax i used -

sed 's/oldtext/newtext/g' file > newfile

Looks like using commas instead of backslashes is better, i couldnt get ur example working with backslashes.
Btw i guess on these two u missed the brackets

$(basename /home/discharge/.bashrc)  $(sed 's,/.*/,,' <<< '/home/discharge/.bashrc') 

@alphaniner - I suppose yours is the best to use, because it has much more options after learning this Parameter expansion topic.

In the end, tried all of them, my script seems to work both ways for bkup and restoring from one, thanks for the tips, would have spent way more time on that if it weren't for you guys

Last edited by Prowler (2012-03-05 22:17:57)

skanky

Member

From: WAIS

Registered: 2009-10-23

Posts: 1,847

Re: Replacing text between backslashes

With Gnu sed you can use most characters instead of the / as a delimiter - check the man page for those you can't use. I picked , at random really.
You don't need the brackets.

I think the main reason why the parameter expansion is best is that it's a bash built-in rather than a separate app (and process), though it is also more flexible generally, with all the options. It isn't portable to (all) other shells though, though with Arch that's probably  not an issue. Also the <<< is a bashism too, but sed could be fed via a pipe, so it's possibly the most portable of the lot - I don't know how ubiquitous basename is.

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Bellum

Member

Registered: 2011-08-24

Posts: 230

Re: Replacing text between backslashes

I use fex for this.

Example:

echo $PWD | fex /{-1}

http://aur.archlinux.org/packages.php?ID=56711

Last edited by Bellum (2012-03-06 02:04:14)

.:B:.

Forum Fellow

Registered: 2006-11-26

Posts: 5,819

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Re: Replacing text between backslashes

As pointed out above bash has it already built in; there's nothing quicker than using that bash functionality unless you're not using bash as your shell - and 90% of the people in this thread will probably fit that description.

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stqn

Member

Registered: 2010-03-19

Posts: 1,191

Website

Re: Replacing text between backslashes

/ is called a slash, \ is a backslash.

Bellum

Member

Registered: 2011-08-24

Posts: 230

Re: Replacing text between backslashes

As pointed out above bash has it already built in; there's nothing quicker than using that bash functionality unless you're not using bash as your shell - and 90% of the people in this thread will probably fit that description.

I use dash for scripts when I can, actually.