SED Worksheet

Our file sedtester contains:

The cat born

11/12/2012 guards the top of the stairs. The dog born 10/14/2013

is scared to cross that cat. That cat is funny.

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Instructions

Just use sed to see the output without actually changing the file (so do not use the -i option). Do use -r to get the extended regex processing.

sed -r 'list of editing commands' filename

list of editing commands is similar to what you can use in VI in command mode.

Remember that the substitution command can use a regular expression

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Write what these will produce when run over the file sedtester

Prework with Grep: Tell which line numbers will be chosen

G1 egrep '[0-9]{4}' sedtester. What number line is chosen?

G2 egrep '[born]' sedtester (Tell me why the last line is chosen.)

G3 egrep 's+' sedtester _____________________________________________

G4 egrep 'cat.*cat' sedtester _____________________________________________

G5 egrep '(.*).*\1' sedtester ____________________________________________

G6 egrep 'the?a?t?' sedtester _____________________________________________

G7 egrep 'the?a?t?' sedtester -o _____________________________________________

Simple sed using VI commands:

1.1. sed 2d sedtester __________________________________________________

1.2. sed = sedtester _________________________________________

1.3. sed iabc sedtester_________________________________________

1.4. sed 2iinsertedLine sedtester_________________________________________

1.5. sed 2cnewstuff sedtester ________________________________________

1.6 sed -n 1,2p sedtester ________________________________________

1.7 sed -n /cat/p sedtester ________________________________________

1.9 sed /cat/d sedtester ________________________________________

1.9 sed -r /cat/!d sedtester ________________________________________

Sed transforming and simple substitution

2.1. sed y/abc/ABC/ sedtester ________________________________________

2.2. sed 2y/abc/ABC/ sedtester ________________________________________

2.4 sed s/cat/goat/ sedtester ________________________________________

2.4 sed s/cat/goat/g sedtester ________________________________________

2.3 sed 2,3s/cat/goat/g sedtester ________________________________________

SED regex

3.1 sed 's/^/Start of line /' sedtester ________________________________________

Note that the single quotes are required

3.2 sed 's/^is/IS/g' sedtester ________________________________________

3.3 sed -r 's/born$/created/' sedtester ________________________________________

Note -r is required

3.4 sed -r 's/[is]/[IS]/' sedtester _______________________________________________

3.5 sed -r 's/is|cat/WORD/' sedtester _______________________________________________

3.6 sed -r 's/(.)\1/DOUBLELETTER/g' sedtester ________________________________

3.7 sed -rn 's/[0-9]/FOUNDNUM/p' sedtester ___________________ __________________

3.8 sed -rn 's/.*([0-9]).*/\1/p' sedtester _______________________________________________

3.9 sed -rn 's/.*([0-9]{2}\/[0-9]{2}\/[0-9]{4}).*/\1/p' sedtester _____________________________

A little grep:

4.0 egrep -o '[0-9]{2}\/[0-9]{2}\/[0-9]{4}' sedtester _____________________________

4.1 egrep 'the|is|or' *

4.2 egrep 'the|is|or' * -l

4.3 egrep '(.)\1' sedtester