Whats wrong with the following command?

Question

I am new to bash. Can someone please point me to the error in the code.

for x in `ls`;do `if(echo $x|grep "-2"); then rm $x; fi`; done;

I am basically trying to remove all the files ending with "-2.jpg"

Answer 1

Don't use command substitution (backquotes) inside your for block. Command substitution is only used for getting the output to be used for assigning to a variable or for evaluating as another command.

`if(echo $x|grep "-2"); then echo 'yo'; fi`

You also need to add a space between if and the expression that follows it:

if (echo $x|grep "-2"); ...

Command substitution is also not necessary:

if echo $x | grep "-2"

You can also use -q to prevent messages being shown from grep:

if echo $x | grep -q "-2"

You also need to use -e to preven -2 from being interpretted as a wrong option to grep:

if echo $x | grep -q -e "-2"

Some of your variables should also be placed inside double quotes to prevent word splitting:

if echo "$x" | grep -q -e "-2"

Prefer $() over backticks when doing command substitution as well:

for x in $(ls);do ...

Finally the better form:

for x in $(ls); do if echo "$x" | grep -q -e "-2"; then echo 'yo'; fi; done

Additional recommendations:

Better not get values through word splitting as it's also subject to pathname expansion and unexpected changes may occur. Use while read loop and process substitution instead. With ls, use -1 as well to show entries line by line:

while IFS= read -r x; do if echo "$x" | grep -q -e "-2"; then echo 'yo'; fi; done < <(ls -1)

When doing command substitution or process substitution, if the last command is a call to an external binary, add exec to prevent unnecessary fork:

$(exec ls -1)
<(exec ls -1)

You can also just use comparisons over using grep:

if [[ $x == *-2* ]]; then

Answer 2

You have to remove the backquotes for the do part, otherwise it means that you want to execute the filename. Also consider this alternative:

for x in `find -name "*-2.jpg"`; do echo $x; echo "yo"; done