sed tricks

Insert

Insert line at the beginning of the file

sed -i '1 i[New string value]' /path/to/file

to any line by number

sed -i '[NUM] i[New string value]' /path/to/file

Replace

Simple replace one value by other

sed -i 's/OldValue/NewValue/g' /path/to/file

Replace /home10/incorrect_path by /home10/correct_path at line that start from Value1 in file /etc/proftpd/user2

sed -ei '/^Value1/ s|/home10/incorrect_path|/home10/correct_path|' /etc/proftpd/user2

Split long line by word count

cat 1.txt 
1 2 3 4 5.3 6,8 7 8 10
a b c d e hh jj kk sds-ds kkoo

cat 1.txt | sed 's/ /\n/3;P;D'
1 2 3
4 5.3 6,8
7 8 10
a b c
d e hh
jj kk sds-ds
kkoo

Delete

Delete line by pattern

sed -i '/Pattern/d' /path/to/file

Delete numbers

sed -i 's/[0-9]*//g' /path/to/file

Delete domains from email

cat 1.txt  | sed 's/@[^ ]*//'

Delete ESC sequences from file

sed -i "s/\x1B\[[0-9;]*[a-zA-Z]//g" /path/to/file

Remove commented by # and empty lines

sed -i 's/#.*$//;/^$/d' /path/to/file

Delete line by number

sed -i [LINE_NUMBER]d /path/to/file

Delete lines from {NUMLINE} to end of file

sed -i '{NUMLINE},$ d' /path/to/file

Delete last line in file

# Linux
sed -i '$d' /path/to/file

# FreeBSD,  MacOS
sed -i '' -e '$ d' /path/to/file