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How to scan a file for literal, return 0 or 1 if found?

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Top Forums Shell Programming and Scripting How to scan a file for literal, return 0 or 1 if found?
# 8  
Old 07-31-2007
Quote:
Originally Posted by kahuna
I think you meant

Code:
if grep -i error filename 1>/dev/null 2>&1
then
echo "found"
else
echo "not found"
fi

No !

with this

Code:
`grep -i error filename 2>/dev/null 1>&2` -eq 0

the return value of grep command is directly equated to the value 0

o - success pattern has been found
other value - pattern not found
# 9  
Old 07-31-2007
Matrix,
Your solution:
Code:
if [ `grep -i error filename 1>/dev/null 2>&1` -eq 0 ]

does not work.

Kahuna is right in fixing your 'if' statement:
Code:
if grep -i error filename 1>/dev/null 2>&1

It is important to note that the option '-i' does not work as it
greps for more than just 'error' and 'ERROR':
'Error', 'eRROR', 'ErRoR', or any other combination of mixed cases.
# 10  
Old 07-31-2007
Quote:
Originally Posted by matrixmadhan
No !
the return value of grep command is directly equated to the value 0
o - success pattern has been found
other value - pattern not found
The code does not work as written. Please try to run it. The return value from grep will not be used in the if statement. Perhaps you meant to add a "-c"?
# 11  
Old 08-02-2007
I accept ! Smilie

Code:
cat test2
pattern

Code:
grep -i pattern test2
if [ $? -eq 0 ]
then
  echo "found"
else
  echo "not found"
fi

Code:
if grep pattern test2 1>/dev/null 2>&1
then
  echo "found"
else 
  echo "not found"
fi

based on success or failure of the grep command
# 12  
Old 08-02-2007
FWIW:
use grep -q to suppress output:

Code:
grep -q 'some string' myfile ; echo $(( ! $? ))

will show 1 if found and 0 if not found - ksh and bash.
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