awk is treat each line as a table, by default space are separators of columns.
General syntax is awk 'search {action}' file_to_parse.
1# Give the value higher than 75000 in column $4
2df | awk '$4 > 75000'
3
4# Print the all line when column $4 is higher than 75000
5df | awk '$4 > 75000 {print $0}'
But if you look for a string, the search need to be included in /search/ or ;search;.
When you print $0 represent the all line, $1 first column, $2 second column etc.
1sed -e 'โฆ' -e 'โฆ' # Several execution
2sed -i # Replace in place
3sed -r # Play with REGEX
4
5# The most usefull
6sed -e '/^[ ]*#/d' -e '/^$/d' <fich.> # openfile without empty or commented lines
7sed 's/ -/\n -/g' # replace all "-" with new lines
8sed 's/my_match.*/ /g' # remove from the match till end of line
9sed -i '4048d;3375d' ~/.ssh/known_hosts # delete lines Number
10
11# Buffer
12s/.*@(.*)/$1/; # keep what is after @ put it in buffer ( ) and reuse it with $1.
13sed -e '/^;/! s/.*-reserv.*/; Reserved: &/' file.txt # resuse search with &
14
15# Search a line
16sed -e '/192.168.130/ s/^/#/g' -i /etc/hosts # Comment a line
17sed -re 's/^;(r|R)eserved:/; Reserved:/g' file.txt # Search several string
18
19# Insert - add two lines below a match pattern
20sed -i '/.*\"description\".*/s/$/ \n \"after\" : \"network.target\"\,\n \"requires\" : \"network.target\"\,/g' my_File
21
22# Append
23sed '/WORD/ a Add this line after every line with WORD'
24
25# if no occurence, then add it after "use_authtok"
26sed -e '/remember=10/!s/use_authtok/& remember=10/' -i /etc/pam.d/system-auth-permanent