UNIX - sed

What is sed

A stream editor 

Syntax 

sed [-n ] Script [ File ...] 
e.g.  sed -n 1p  /some/file/name.txt > test.txt



sed [-n ] [-e  Script ] ... [-f ScriptFile] [ File ...] 

For example, with the script sed -e '1d' my/input/file >my/output/file, you could put '1d'  in a file known as MyScriptFile, and then it will appear as:
sed -e -f MyScriptFile my/input/file >my/output/file



-------MyScriptFile-----------
1d 

---------------------------------
Note that commands are _without_ quotes int his file!


Few sed examples:

Print only the first line of a file

sed -n 1p  /some/file/name.txt > test.txt

Print only the 2^nd line of a file

sed -n 2p  /some/file/name.txt >test.TXT 

Start copying from first line and end at third:

sed -n 1,3p  /some/file/name.txt >test

Delete line number 1 and then write it to the output…could be helpful in cases, e.g. where you like to delete the header from a SQL output

sed -e '1d' my/input/file >my/output/file