env loop

bengoavs · 01-04-2008, 11:21 AM

Yo!

I need a loop that would go through each line of the env.
Should be simple.

TNX!!!

Tinkster · 01-04-2008, 01:02 PM

for i in `env`; do something; done

Cheers,
Tink

bengoavs · 01-04-2008, 02:22 PM

That's actually what I've done but get some strange lines.
Here's the output of diff between manual env and script env echoing:
What are those 2435, 22 ?? I want it to be identical to manual env

Code:

benw@aoilinux1/~/bash$ diff /tmp/auto /tmp/manu
2d1
< TERM=xterm
3a3
> TERM=xterm
5,7c5,6
< SSH_CLIENT=::ffff:172.19.187.27
< 2435
< 22
---
> SSH_CLIENT=::ffff:172.19.187.27 2435 22
> OLDPWD=/home/benw
12d10
< MAIL=/var/spool/mail/benw
14,15c12
< _=/bin/env
< INPUTRC=/etc/inputrc
---
> MAIL=/var/spool/mail/benw
16a14
> INPUTRC=/etc/inputrc
17a16
> PS1=\[\e[32m\]\u@\h/\[\e[1;31m\]\w\[\e[1;34m\]\$\[\e[0m\]
19d17
< SHLVL=3
20a19
> SHLVL=2
22,27c21,22
< SSH_CONNECTION=::ffff:172.19.187.27
< 2435
< ::ffff:172.29.37.9
< 22
< LESSOPEN=|/usr/bin/lesspipe.sh
< %s
---
> SSH_CONNECTION=::ffff:172.19.187.27 2435 ::ffff:172.29.37.9 22
> LESSOPEN=|/usr/bin/lesspipe.sh %s
28a24
> _=/bin/env

colucix · 01-04-2008, 03:19 PM

Quote:

< SSH_CLIENT=::ffff:172.19.187.27
< 2435
< 22

> SSH_CLIENT=::ffff:172.19.187.27 2435 22

Your script does not manage blank spaces in the correct way. If you post the content of the script it would be easier to explain.

bengoavs · 01-05-2008, 01:24 AM

Code:

for i in `env`
do
echo "$i"
done

colucix · 01-05-2008, 04:55 AM

Well... before the shell executes the for loop, it substitutes the output of the env command so it truly executes something like the following

Code:

for i in LESS=-M -I LESSOPEN=lessopen.sh %s LESSCLOSE=lessclose.sh %s %s and so on ...
do
  echo $i
done

that is it considers a long list of strings (fields) separated by blank spaces and execute the command inside the loop one by one. To prevent this behavior (splitting a long string by blank spaces) you have to modify the value of the Input Field Separator, which is stored in the shell variable IFS. The correct way is:

Code:

# Store the original IFS
OLD_IFS=${IFS}

# Set IFS to 'newline'
IFS=$(echo)

# Now execute the loop splitting the string by newlines instead of blank spaces
for i in $(env)
do
   echo $i
done

# Restore the original IFS
IFS=${OLD_IFS}

Note that the syntax $(command) is equivalent to `command`. See man bash, section "Command substitution" for details.

unSpawn · 01-05-2008, 06:22 AM

If you don't need to operate on elements you could also echo complete lines: 'env|while read i; do echo "$i"; done'