how do I remove a variable from PATH

melinda_sayang · 08-05-2004, 05:11 AM

export PATH=$PATH:/blablabla/blablabla

Now, how do I remove /blablabla/blablabla from $PATH environment variable?
Thank you.

gbonvehi · 08-05-2004, 06:08 AM

You have to set the variable again, of course, you have to make a script to remove that piece from it and then set it again.

theYinYeti · 08-05-2004, 06:51 AM

PATH=$(echo "$PATH" | sed 's/:/\n/g' | grep -vFx "/blablabla/blablabla" | awk '{ORS=":";print $0}' | sed 's/:$//')

Yves.

Cedrik · 08-05-2004, 07:50 AM

or :
PATH=$(echo $PATH | perl -pe 's/\/blabla\/blabla:?//')

theYinYeti · 08-05-2004, 08:11 AM

You're right, Cedrik.

But your solution (equivalent to sed, BTW) has two drawbacks:
- It will "hurt" (don't know the right word), but not remove, the paths that only *contain* the pattern. Example: let's say /bla/bla is /bin; you want to remove /bin from the PATH, then with your method, /usr/bin will become /usr, /usr/X11R6/bin will become /usr/X11R6, and so on (or worse, as the : will surely get removed too).
- It will work for the path you write "by hand", and only this one. And you have to rework the path based on your knowledge of regular expressions. It's OK for running it directly from the prompt, and even then you have to be good at regular expressions. But integration into a script would involve some preparation (with automatic adding of escape characters at the right places), like that:

pathRE=$(echo "$1" | sed -e 's/\./\\./g' -e [...and so on for {}'."/^$...])
PATH=$(echo $PATH | eval perl -pe "'s/"${pathRE}":?//'")

which doesn't help for the first problem anyway.
I hope this helps. I only want to share knowledge. Myself, I didn't know it was so easy to use perl expressions on the command line

Yves.

Cedrik · 08-05-2004, 08:22 AM

Well, I didn't think of the /bin remove thing

I think you right but note that the perl expression in my post above fails only if you want to remove /bin from the PATH so in practice...
At least thanks for the comment, and point to the exeption.

[edit]
Here is another suggestion that take in account the /bin exeption :

Code:

PATH=$(echo $PATH | perl -ne '@s=split /:/,$_;while(@s){$b=shift @s;unless($b=~/^\/bin$/){print "$b:";}}')

melinda_sayang · 08-05-2004, 11:01 AM

I am sorry. I don't understand. I want to remove /mnt/gudang/NWN/program/jdk1.5.0/bin from PATH environment variable. This is my script.
PATH=$(echo "$PATH" | sed 's/:/\n/g' | grep -vFx "/mnt/gudang/NWN/program/jdk1.5.0/bin" | awk '{ORS=":";print $0}' | sed 's/:$//')
export PATH="/usr/lib/java/bin":"{$PATH}"

I use java 1.5 as default. But sometimes I want to use java 1.4.2. Java 1.5 is in /mnt/gudang/NWN/program/jdk1.5.0/bin and java 1.4.2 is in /usr/lib/java/bin. That script does not work. Please make it clearer.

Thank you.

Cedrik · 08-05-2004, 11:07 AM

Code:

# to replace /mnt/gudang/NWN/program/jdk1.5.0/bin
# by /usr/lib/java/bin
# try :

PATH=$(echo $PATH | perl -pe 's#/mnt/gudang/NWN/program/jdk1.5.0/bin#/usr/lib/java/bin#')
export PATH

# to replace /usr/lib/java/bin
# by /mnt/gudang/NWN/program/jdk1.5.0/bin
# try :

PATH=$(echo $PATH | perl -pe 's#/usr/lib/java/bin#/mnt/gudang/NWN/program/jdk1.5.0/bin#')
export PATH

theYinYeti · 08-06-2004, 03:28 AM

Quote:

I don't understand [...] This is my script.
PATH=$(echo "$PATH" | sed 's/:/\n/g' | grep -vFx "/mnt/gudang/NWN/program/jdk1.5.0/bin" | awk '{ORS=":";print $0}' | sed 's/:$//')
export PATH="/usr/lib/java/bin":"{$PATH}"

Last line should be:
export PATH=/usr/lib/java/bin:${PATH}
But then if you make a script, you'd rather make that: useJava.sh

Code:

#!/bin/bash
# Use the java version given by $1 (eg: 142 or 150)

# Here you put the versions that are installed:
MYJAVA142=/usr/lib/java
MYJAVA15=/mnt/gudang/NWN/program/jdk1.5.0

# go!
JAVA_HOME=$(eval echo \"\$MYJAVA$1\")
if [ -z "$JAVA_HOME" ]; then
  echo "Version $1 of Java is not installed." >&2
  exit 1
fi

JPATHS=$(eval echo -ne \"$(echo "${!MYJAVA*} " | sed 's/\([^ ]*\) /${\1}\\n/g')\" | sed 's|$|/bin|')
PATH=$(echo "$PATH" | sed 's/:/\n/g' | grep -vFx "$JPATHS" | awk '{ORS=":";print $0}' | sed 's/:$//')
PATH=${JAVA_HOME}/bin:${PATH}

export PATH JAVA_HOME

I hope I did not write any mistake. I cannot test what I just wrote.

Yves.

melinda_sayang · 08-06-2004, 04:56 AM

I don't know what's wrong? This script does not work. I don't understand.

Code:

#!/bin/bash

export PATH=/usr/lib/java/bin:{$PATH}

I run this script thousand times. And yet /usr/lib/java/bin does not included in $PATH. But when I do this command:
export PATH=/usr/lib/java/bin:{$PATH}
or
export PATH=/usr/lib/java/bin:$PATH

I can include /usr/lib/java/bin in $PATH. So is there any wrong with my bash.

crackpipe · 02-27-2009, 02:45 PM

Um, wouldn't it just be easier to remove it from your "etc/profile" file?

Alien Bob · 02-27-2009, 02:52 PM

What's this sudden influx of newbies trying to revive the corpses of dead threads? This one is nearly 5 years old!

Eric

brianL · 02-27-2009, 04:24 PM

Yes, there's a plague of zombie threads, Eric. Be afraid...be very afraid.

onebuck · 02-27-2009, 09:13 PM

Hi,

Yes, We can!

Shucks, wrong forum.

bgeddy · 02-27-2009, 09:33 PM

This is really starting to bug me. Will all users please not resurrect long dead threads as seems to be happening more and more here. This serves no purpose as the OP will probably have long solved their problem. It just tends to make the forum chaotic and irrelevant - in other words a mess. Lets not turn this place into a joke littered with dredged up crap.

I know I'm guilty of responding to an ancient thread here but this seems to be happening more and more and it's driving me nuts. Please check the post dates before adding to a thread.