How to grep for tab character(s) in Linux
Answer:
To grep for file contains tab characters, you can execute the command below:
# grep $'\t' input.txt
Only show filenames in grep command
Answer:
Sometimes you want the grep command only return the filenames that matched a pattern, you can try the following:
# grep -r -l "foo" .
The key is the -l option.
How to use sed to simulate grep -v?
Answer:
There are two methods to simulate grep -v (print out line(s) if not match) in sed.
# sed -n '/regexp/!p'
or
# sed '/regexp/d'
How to grep a string in a binary file?
Answer:
Assume you have a binary file "foo.bin", you can combine strings with the grep command.
strings foo.bin | grep bar
Jan 072009
Remove empty lines in a file
Answer
Pick any one of the following methods.
1. grep
grep . test.txt
2. sed
sed '/^$/d' test.txt
3. awk
awk NF test.txt
4. tr
cat test.txt | tr -s "\n"
5. perl
perl -n -e 'print unless /^$/' test.txt
