search a string in Shell script variable - shell

I have a shell script variable
$a = "Hello i am pass"
now i want to search for "pass" in variable $a.
if ["$a" == "pass"]; then
echo "`Success`"
else
echo "`fail`"
fi
Please give me shell script for searching pass keyword to use in above code.


Try with this,
#!/bin/bash
a="Hello i am pass";
if [ `echo $a | grep -c "pass" ` -gt 0 ]
then
echo "Success"
else
echo "Fail";
fi


flag=`echo $a|awk '{print match($0,"pass")}'`;
if [ $flag -gt 0 ];then
echo "Success";
else
echo "fail";
fi


Here is a more compact way to write this:
echo "$a" | grep "pass" && echo "Found." || echo "Not found."
You can use braces to put in multiple instructions instead of a simple echo:
echo "$a" | grep "pass" && {echo "Found.";exit 0} || {echo "Not found.";exit 1}


today i used extended choice parameter and using execute shell for the string match.
if someone will find same problem anyone can use this
if [ `echo $test| grep -c "abc" ` -gt 0 ]
then
echo "Success"
else
echo "Fail";
fi


Try this
a="Hello I am Pass";
a1="Hello, Passed my First Attempt"
a2="Passed in First Attempt"
if [[ ${a,,} =~ 'pass' ]]; then echo 'Success'; else echo 'First Attempt in Learning'; fi


Short command:
OPC="test"
PROD="This is a test"
[[ ${PROD,,} =~ $OPC ]] && echo -n 1 || echo -n 0
The answer will be "1" when find "OPC" in "PROD".

Related

Check parameters of script in bash

I wanna write a script which check variables of this script.
I have tried some, but it isn't working. The idea is:
If on of the parameters is a number, print that it is number
If on of the parameters is a character, print that it is character
If 'man parameter' is executable, print that it is might be a function
Script I have tried:
#!/bin/bash
echo Hello $LOGNAME'!'
test $# -eq 0 && echo 'Try again, no parameters were entered' || echo 'Num of parameters is '$#
re='^[0-9]+$'
for i in $*
do
if ![["$i" =~ $re]];then
echo 'Parameter '$i' is alphabetical'
else
if [["$i" =~ $re]];then
echo 'Parameter '$i' is digital'
else
if [ $i];then
echo $i' might be a function. Try to use man of --help'
fi
fi
fi
done

#!/bin/bash
echo "Hello ${LOGNAME}!"
[ "$#" -eq 0 ] && { echo 'Try again, no parameters were entered'; exit 1; }
echo 'Num of parameters is '$#
re='^[0-9]+$'
for i in "$#"
do
if ! [[ "$i" =~ $re ]];then
echo "Parameter '$i' is alphabetical"
man "$i" > /dev/null 2> /dev/null
if [ "$?" -eq 0 ];then
echo "$i might be a function. Try to use man of --help"
fi
else
echo "Parameter '$i' is digital"
fi
done;
When you write a test you need spaces around your brackets.
You can easily find and fix those bugs if you use shellcheck

If statement returning error in shell script? [duplicate]

I would like to write in one line this:
if [$SERVICESTATEID$ -eq 2]; then echo "CRITICAL"; else echo "OK"; fi
So to do a test in my shell I did:
if [2 -eq 3]; then echo "CRITICAL"; else echo "OK"; fi
The result is
-bash: [2: command not found
OK
So it doesn't work.

Space -- the final frontier. This works:
if [ $SERVICESTATEID -eq 2 ]; then echo "CRITICAL"; else echo "OK"; fi
Note spaces after [ and before ] -- [ is a command name! And I removed an extra $ at the end of $SERVICESTATEID.
An alternative is to spell out test. Then you don't need the final ], which is what I prefer:
if test $SERVICESTATEID -eq 2; then echo "CRITICAL"; else echo "OK"; fi

Write like this, space is required before and after [ and ] in shell
if [ 2 -eq 3 ]; then echo "CRITICAL"; else echo "OK"; fi

Shorter format.
( [ 2 -eq 3 ] && echo "CRITICAL" ) || echo "OK"

Regex pattern type numbers : 10,12.1,+3.33,-1,0004,-48.9
Oneliner attacks again!
( [ `echo $number 2>/dev/null | grep -E "^[ ]*(\+|\-){0,1}[0-9]+(\.[0-9]+)?$"` ] && echo "NUMBER" ) || echo "NOT NUMBER"

How to write if else in one line in shell?

I would like to write in one line this:
if [$SERVICESTATEID$ -eq 2]; then echo "CRITICAL"; else echo "OK"; fi
So to do a test in my shell I did:
if [2 -eq 3]; then echo "CRITICAL"; else echo "OK"; fi
The result is
-bash: [2: command not found
OK
So it doesn't work.

Space -- the final frontier. This works:
if [ $SERVICESTATEID -eq 2 ]; then echo "CRITICAL"; else echo "OK"; fi
Note spaces after [ and before ] -- [ is a command name! And I removed an extra $ at the end of $SERVICESTATEID.
An alternative is to spell out test. Then you don't need the final ], which is what I prefer:
if test $SERVICESTATEID -eq 2; then echo "CRITICAL"; else echo "OK"; fi

Write like this, space is required before and after [ and ] in shell
if [ 2 -eq 3 ]; then echo "CRITICAL"; else echo "OK"; fi

Shorter format.
( [ 2 -eq 3 ] && echo "CRITICAL" ) || echo "OK"

Regex pattern type numbers : 10,12.1,+3.33,-1,0004,-48.9
Oneliner attacks again!
( [ `echo $number 2>/dev/null | grep -E "^[ ]*(\+|\-){0,1}[0-9]+(\.[0-9]+)?$"` ] && echo "NUMBER" ) || echo "NOT NUMBER"

Shell SH : how to find if a string is present in a variable with egrep?

For a small script shell sh
I would like to know if "of" or "the" or "is" is present in the variable Toto
Toto="Planet of the world"
Test= $(egrep -c '(of|the|is)' "$Toto")
if $Test > 0; then echo "OK"; else echo "NO"
But this code does not work ....
Somebody could help me ?

Toto="Planet of the world"
Test=$(echo $Toto | grep -c "of\|the\|is")
if [[ $Test -gt 0 ]]
then
echo "OK";
else
echo "NO";
fi
Shorter :
Toto="Planet of the world"
Test=$(echo $Toto | grep -c "of\|the\|is")
[[ $Test -gt 0 ]] && echo "OK" || echo "NO";

Try with a pipeline, like this:
$ Toto="Planet of the world"
$ test="$Toto | egrep '(of|the|is)'"
$ if [ "$test" > 0 ] ; then echo 'OK'; else echo 'NO'; fi

check if a line is empty using bash

I am trying to do a simple comparison to check if a line is empty using bash:
line=$(cat test.txt | grep mum )
if [ "$line" -eq "" ]
then
echo "mum is not there"
fi
But it is not working, it says: [: too many arguments
Thanks a lot for your help!

You could also use the $? variable that is set to the return status of the command. So you'd have:
line=$(grep mum test.txt)
if [ $? -eq 1 ]
then
echo "mum is not there"
fi
For the grep command if there are any matches $? is set to 0 (exited cleanly) and if there are no matches $? is 1.

if [ ${line:-null} = null ]; then
echo "line is empty"
fi
or
if [ -z "${line}" ]; then
echo "line is empty"
fi

The classical sh answer that will also work in bash is
if [ x"$line" = x ]
then
echo "empty"
fi
Your problem could also be that you are using '-eq' which is for arithmetic comparison.

grep "mum" file || echo "empty"

if line=$(grep -s -m 1 -e mum file.txt)
then
echo "Found line $line"
else
echo 'Nothing found or error occurred'
fi

I think the clearest solution is using regex:
if [[ "$line" =~ ^$ ]]; then
echo "line empty"
else
echo "line not empty"
fi

If you want to use PHP with this,
$path_to_file='path/to/your/file';
$line = trim(shell_exec("grep 'mum' $path_to_file |wc -l"));
if($line==1){
echo 'mum is not here';
}
else{
echo 'mum is here';
}

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