Linux Ask! is a Q & A web site specific for Linux related questions. Questions are collected, answered and audited by experienced Linux users.
Multiple separators in awk
Answer:
Sometimes when you split a string using awk, you need to support more than 1 separators, you can use the -F option.
E.g.
# cat foo.txt | awk -F "[ ?]" '{print $7}'
Now the awk split by a space and by a ?.
Extract column data using awk
Answer:
A simple awk command print the 1st column of top command
# top -bc -n1 | awk '{print $1}'
If you want to specify the field separator, you can do the following
# awk -F':' '{print $1}' /etc/passwdWhich print the 1st column of file /etc/password, as if they are split by :
How to remove BOM from UTF-8?
Answer:
# awk '{if(NR==1)sub(/^\xef\xbb\xbf/,"");print}' text.txt
Source: http://stackoverflow.com/questions/1068650/using-awk-to-remove-the-byte-order-mark
Updated: (Suggested by Van Overveldt Peter)
# tail --bytes=+4 text.txt
Remove empty lines in a file
Answer
Pick any one of the following methods.
1. grep
grep . test.txt
2. sed
sed '/^$/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
