Shell Programming and Scripting

Using ksh.
Looks like the problem is the platform.
Tested using

Code:

cat /tmp/t.txt |sed "s/old/new/g">/tmp/t.txt; cat /tmp/t.txt

File is empty on AIX (IBM) and SunOS.
It worked on HPUX.

Moderator's Comments:

Please use CODE tags when displaying sample input, output, and code segments.

intersting .. must be more than platform ... because I tested it on AIX (5.3 TL05) and Kubunto (7.10) and it worked ...

AIX 5.3 (how do you distinguish further? Not seeing anything more in uname -a )

The TL comes from my SA ... sorry

If I remember correctly older versions of bash doesnt support reading a file and redirecting output to the same on the same command line. I use version 2.xxx at work and it doesnt work there.

On ksh, I seem to remember that it also depends on your version- what version are you using?

I suggest you go with Klashxx's perl pie solution, but adapted so that you use a separator char which isnt so usual in filenames:

Code:

perl -p -i -e "s|$replacethis|$withthis|g" filename

I agree the perl route is better ... it also works from within a shell as well. I was just trying to answer the original question, there may be other reasons as to why they need it to be part of a script. (like a class assignment)

I am running bash 3.2.5 & kde 93

This is a sed solution using backup file.

Code:

sed -i .bak "s/'$old'/'$new'/g" $1 && rm $i.bak