[SOLVED] add a line before each found pattern in bash. using the found pattern

Issue

I have a file that list the attributes found using ldap search like this

dsee_simpleauthbinds{cn="1389"} 141962
dsee_simpleauthbinds{cn="1636"} 1029264
dsee_wholesubtreesearchops{cn="1389"} 1638369
dsee_wholesubtreesearchops{cn="snmp"} 35862

the attributes are grouped together in 'sessions' eg the wholesubtreesearchops attribute is grouped with all the cn where that attribute is present.

I need to modify the file so that for each attribute, the attribute is added before the start of the session so the file above becomes this:

[dsee_simpleauthbinds]
dsee_simpleauthbinds{cn="1389"} 141962
dsee_simpleauthbinds{cn="1636"} 1029264      
[dsee_wholesubtreesearchops]
dsee_wholesubtreesearchops{cn="1389"} 1638369
dsee_wholesubtreesearchops{cn="snmp"} 358629

of course there are far more attributes the idea would be before each new attribute found in the file add the header in the line just before it.

Solution

Assumptions:

• data is already sorted by attribute
• the only requirement is to add a [<attribute>] line, ie, the node="...", strings in the expected output are typos; otherwise OP needs to update the question with the details on where the node="...", strings are coming from

Sample input data:

$ cat attrib.dat
dsee_simpleauthbinds{cn="1389"} 141962
dsee_simpleauthbinds{cn="1636"} 1029264
dsee_wholesubtreesearchops{cn="1389"} 1638369
dsee_wholesubtreesearchops{cn="snmp"} 35862

One awk idea:

awk -F'{' '$1 != header {print "[" $1 "]"; header=$1}1' attrib.dat

This generates:

[dsee_simpleauthbinds]
dsee_simpleauthbinds{cn="1389"} 141962
dsee_simpleauthbinds{cn="1636"} 1029264
[dsee_wholesubtreesearchops]
dsee_wholesubtreesearchops{cn="1389"} 1638369
dsee_wholesubtreesearchops{cn="snmp"} 35862

Answered By - markp-fuso

Answer Checked By - Mary Flores (WPSolving Volunteer)