I have a ksh script that returns a long list of values, newline separated, and I want to see only the unique/distinct values. It is possible to do this?
For example, say my output is file suffixes in a directory:
tar gz java gz java tar class class
I want to see a list like:
tar gz java class
Pipe them through sort
and uniq
. This removes all duplicates.
uniq -d
gives only the duplicates, uniq -u
gives only the unique ones (strips duplicates).
./script.sh | sort -u
This is the same as monoxide's answer, but a bit more concise.
With zsh you can do this:
% cat infile
tar
more than one word
gz
java
gz
java
tar
class
class
zsh-5.0.0[t]% print -l "${(fu)$(<infile)}"
tar
more than one word
gz
java
class
Or you can use AWK:
% awk '!_[$0]++' infile
tar
more than one word
gz
java
class
Unique, as requested, (but not sorted);
uses fewer system resources for less than ~70 elements (as tested with time);
written to take input from stdin,
(or modify and include in another script):
(Bash)
bag2set () {
# Reduce a_bag to a_set.
local -i i j n=${#a_bag[@]}
for ((i=0; i < n; i++)); do
if [[ -n ${a_bag[i]} ]]; then
a_set[i]=${a_bag[i]}
a_bag[i]=$'\0'
for ((j=i+1; j < n; j++)); do
[[ ${a_set[i]} == ${a_bag[j]} ]] && a_bag[j]=$'\0'
done
fi
done
}
declare -a a_bag=() a_set=()
stdin="$(</dev/stdin)"
declare -i i=0
for e in $stdin; do
a_bag[i]=$e
i=$i+1
done
bag2set
echo "${a_set[@]}"
With AWK you can do, I find it faster than sort
./yourscript.ksh | awk '!a[$0]++'
I get a better tips to get non-duplicate entries in a file
awk '$0 != x ":FOO" && NR>1 {print x} {x=$0} END {print}' file_name | uniq -f1 -u
For larger data sets where sorting may not be desirable, you can also use the following perl script:
./yourscript.ksh | perl -ne 'if (!defined $x{$_}) { print $_; $x{$_} = 1; }'
This basically just remembers every line output so that it doesn't output it again.
It has the advantage over the "sort | uniq
" solution in that there's no sorting required up front.
Source: Stackoverflow.com