Recipe: Playing with xargs

Convert multiple line input into single line output
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$ cat example.txt # Example file
1 2 3 4 5 6 
7 8 9 10 
11 12

$ cat example.txt | xargs
1 2 3 4 5 6 7 8 9 10 11 12 


Convert single/multiple line into 3 line output
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$ cat example.txt | xargs -n 3
1 2 3 
4 5 6 
7 8 9 
10 11 12

Delimiter to split lines
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$ echo "splitXsplitXsplitXsplit" | xargs -d X
split split split split
# Here we used -d X hence X is replaced with " " which is Internal Field Separator.

Passing stdin as arguments by format in a line
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$ cat files.txt
file1
file2
file3
# Each of the files exist and contain text "hello"

$ cat files.txt | xargs
file1 file2 file3
# Converted column wise to linear arguments format. Now supply this argument to a command.

$ cat files.txt | xargs -I {} cat {}
hello
hello
hello

Arguments atonce and iterative execution
========================================
$ cat file1;cat file2;cat file3

$ cat files.txt | xargs wc -l
 1 file1 
 1 file2 
 1 file3 
 3 total 
# Use without -I
# It is equivalent to wc -l file1 file2 file3
# wc is for word count


xargs with find
===============
$ find . -type f -name "*.txt" -print0 | xargs -0 rm -f
# Removes all .txt fes

Count LOC
=========
$ find source -type f -name "*.c" -print0 | xargs -0 wc -l

Subshell trick with stdin
=========================
$ cat files.txt  | ( while read arg; do cat $arg; done )
# Equivalent to  cat files.txt | xargs -I {} cat {}