Shell Programming and Scripting

Guys i'm trying to save STDERR to a variable for a portion of my ksh script on solaris.

I know i can create redirects to files as such:

exec 4>/tmp/lava
print "This will be saved to /tmp/lava and not screen"; >&4
print "This will be seen on screen" >&2

I want to save the STDOUT of a command to a variable and save STDERR to another without having to have files everywhere.

e.g tapelist=$( command blah blah )

I then want to check if tapelist contains anything and run stuff otherwise dont
i.e

if [[ -n "{tapelist}" ]];then
do stuff....
else
do other stuff
fi

If the command fails it produces STDERR output i want to save so i can print it out later.

So in my thoughts although i know this doesnt work :-

savestderr="";
exec 3>${savestderr}
tapelist=$(command blah blah 2>&3)

Then can reference the error message as ${savestderr} Any ideas?

hm the only way I know, to split stdout and stderr to varialbes, without using files, is to run the command twice

short example:

eg.:

Code:

stderr=$(ls /opt /bla 2>&1 1>/dev/null )
stdout=$(ls  /opt /bla 2>/dev/null)

Code:

echo $stderr
ls: 0653-341 The file bla does not exist.

Code:

echo $stdout
opt:  IBM IBMinvscout csm diagnostics freeware hsc ibm_help lost+found perl

if you modify something with your command, you can't use this method

Thanks Dude,

I wonder which is less expensive.

Guess i'm going down the file route

Code:

2>${TMP}/$(basename $0).stderr

Cheers

Use

Code:

exec 2>${TMP}/$(basename $0).stderr

inside the script.

If I want stderr and stdout in variables, I would do it this way

Code:

stdout=$(ls /bla /opt 2>/tmp/stderr.txt)
stderr=$(cat /tmp/stderr.txt)

an then remove the file, or use it for other commands in the script


normally, to check if a command fails or not, you check the return code $?

for just later reading it, to see what happens, you should use a file