Related to this issue atom/atom#16120 , I've found that the package pigments cause atom to freeze when trying to open multiple files from CLI.

Please follow theses step to reproduce the bug :

FILES="";

for i in $(seq 1 15)
do
    echo "File #$i" > "file_$i.txt";
    FILES="${FILES} file_${i}.txt";
done

echo "atom${FILES}"

Execute the following command :

atom file_1.txt file_2.txt file_3.txt file_4.txt file_5.txt file_6.txt file_7.txt file_8.txt file_9.txt file_10.txt file_11.txt file_12.txt file_13.txt file_14.txt file_15.txt

When disabling pigment package, the 15 files successfully opens without freezing atom. When enabling this package, atom freeze, and the OS (Ubuntu 16.04) freeze too (the mouse cursor move very slowly)