Adding strings in shell script

[mariocq]

Hello:

I want to make the following
XXX:#cat prueba.txt
uno
dos
tres
cuatro

---------
#!/usr/bin/sh -x
comando="grep -e uno -e dos prueba.txt"
comando="$comando |grep dos"
$comando
----------------
but instead executing the comand
grep -e uno -e dos prubea.txt|grep dos
I obtain the following:
-----------------------------------
+ comando=grep -e uno -e dos prueba.txt
+ comando=grep -e uno -e dos prueba.txt |grep dos
+ grep -e uno -e dos prueba.txt |grep dos
prueba.txt:uno
prueba.txt:dos
grep: can't open |grep
grep: can't open dos
-----------------

Any ideas

 

[p5wizard]

for multiple grep strings, use egrep 'str1|str2'

also, you want to use the eval builtin, in order to recheck for special characters like pipe symbol which in your example is not visible to the shell until the variable comando is expanded, but at that stage, the pipe symbol has lost its special meaning.

#!/usr/bin/sh -x
comando="egrep 'uno|dos' prueba.txt"
comando="$comando |grep dos"
eval $comando

HTH,

p5wizard

 

[PHV]

Try this:
eval $comando

Hope This Helps, PH.
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