Show certain lines by line number: Difference between revisions
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== Approaches == | == Approaches == | ||
=== Using cat, head & tail commands === | === Approach 1: Using cat, head & tail commands === | ||
1. key-in the command<ref>[https://unix.stackexchange.com/questions/288521/with-the-linux-cat-command-how-do-i-show-only-certain-lines-by-number text processing - With the Linux "cat" command, how do I show only certain lines by number - Unix & Linux Stack Exchange]</ref> | 1. key-in the command<ref>[https://unix.stackexchange.com/questions/288521/with-the-linux-cat-command-how-do-i-show-only-certain-lines-by-number text processing - With the Linux "cat" command, how do I show only certain lines by number - Unix & Linux Stack Exchange]</ref> | ||
<pre> | <pre> | ||
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</pre> | </pre> | ||
=== Using sed command === | === Approach 2: Using sed command === | ||
key-in the command<ref>[https://www.gnu.org/software/sed/manual/sed.html#Common-Commands sed, a stream editor]</ref> | key-in the command<ref>[https://www.gnu.org/software/sed/manual/sed.html#Common-Commands sed, a stream editor]</ref> | ||
<pre> | <pre> | ||
Revision as of 12:40, 1 December 2019
Show certain lines by line number of string file
Prepare the testing text file
echo "line 1" > test.txt echo "line 2" >> test.txt echo "line 3" >> test.txt echo "line 4" >> test.txt echo "line 5" >> test.txt echo "line 6" >> test.txt
Approaches
Approach 1: Using cat, head & tail commands
1. key-in the command[1]
# X: start line number # Y: end line number X=2 Y=4 Z=$(($Y-$X+1)) cat test.txt | head -n $Y | tail -n $Z
result
line 2 line 3 line 4
2. key-in the command if you want to show the line number of each line
# X: start line number # Y: end line number X=2 Y=4 Z=$(($Y-$X+1)) cat -n test.txt | head -n $Y | tail -n $Z
result
2 line 2
3 line 3
4 line 4
Approach 2: Using sed command
key-in the command[2]
# X: start line number # Y: end line number X=2 Y=4 Z=$(($Y-$X+1)) sed -n -e "$X,$Y p" -e "$Y q" test.txt
result
line 2 line 3 line 4