Want to 1st test sed stmt

[cptk]

How can I 1st test to see if a sed command works before actually running the command?

For eaxmple:
> sed '1,5 s/\<searchdata\>/replacedata/' filename

One solution I've come-up is ...
> sed '1,5 s/\<searchdata\>/replacedata/' filename | grep replacedata

then check the exit status (e.g. $?)

...is there a better way?

 

[TonyGroves]

You could pipe the output to diff which would show you the changes, without affecting the file:
[tt]
sed '1,5s/\<searchdata\>/replacedata/' filename | diff - filename
[/tt]

 

[PHV]

And what about this ?
sed [!]-n[/!] '1,5 s/\<searchdata\>/replacedata/[!]p[/!]' filename

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[cptk]

PHV -

I went with your recommendation ...

if [ -n "`sed -n '1,5 s/\<searchdata\>/replacedata/p' filename`" ]
then ...

thanks!!!

[Note: -n checks if string is non-zero length]