UNIX for Dummies Questions & Answers

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I have scripting question.
I have a file "out.txt"

which is generated by another script

the file contains the following

Code:

my_identifier8859574

logout

The number is generated in the script and I have put the my_identifier bit in front of it as a unique identifier

I now have another script which uses this file, It needs the number Only that comes after my_identifier

I havn't a breeze how to do this.
I assume i need to use awk

something like

VALUE=cat out.txt | grep my_identifier | awk .....

any suggestions?
Cheers
Graham

Is my_identifier always the first line or it could be anywhere in out.txt?

If 1:

Code:

id=$(read<out.txt;printf "%s" "${REPLY#my_identifier}")

else:

Code:

id="$(fgrep my_identifier out.txt)" id="${id#my_identifier}"

thank you kindly

this works perfectly

Apologies for asking again

but I am now having an issue with TR

I want to make double sure that the value of id has no non-numerical characters in it.

Code:

if [ ($id | tr -d '[:digit:]') == '' ]
then
#let do the next bit
else
#email me
fi

my if syntax is not correct though

im getting the error
./test.sh[12]: Syntax error at line 12 : `(' is not expected.

any advice?
Cheers
Graham

Use case:

Code:

case "$id" in
  "" | *[!0-9]* ) # email me ;;
              * ) # let do the next bit ;;
esac

if [ -z "`echo $id | tr -d [0-9]`" ]
then
echo "Valid"
else
echo "Invalid"
fi

thank you very much sir

Graham