Shell Commands

shuf

cut

tr

lp

sort

Options:

-t, --field-separator=SEP
    use SEP instead of non-blank to blank transition

-k, --key=POS1[,POS2]
    start a key at POS1 (origin 1), end it at POS2 (default end of line)

-h, --human-numeric-sort
    compare human readable numbers (e.g., 2K 1G)

-n, --numeric-sort
    compare according to string numerical value

nproc

print the number of processing units avaiable.

od / xxd / hexdump

read the binary file.

Notes: byte order

$ echo -n "ABCD" | xxd
00000000: 4142 4344                                ABCD
$ echo -n "ABCD" | hexdump
0000000 4241 4443                              
0000004

Reference

comm / diff / tkdiff / cmp

Can be used to compare binary or non-binary files.

comm

compare two sorted files line by line.

$ cat file1.txt 
apple
banana
cherry

$ cat file2.txt 
banana
cherry
date
erase

$ comm file1.txt file2.txt 
apple
                banana
                cherry
        date
        erase

The file must be sorted before using the comm command. Otherwise it will complain that:

comm: file 1 is not in sorted order

and cannot work correctly. For example,

$ cat file1.txt 
apple
cherry
banana

$ cat file2.txt 
banana
cherry
date
erase

$ comm file1.txt file2.txt 
apple
        banana
                cherry
comm: file 1 is not in sorted order
banana
        date
        erase
comm: input is not in sorted order

diff

Syntax:

diff -u file1 file2

Options:

-e, --ed
    output an ed script

-u, -U NUM, --unified[=NUM]
    output NUM (default 3) lines of unified context
    (that is, print NUM lines before and after the difference line)

tkdiff

Use a GUI to display the differences.

cmp

Prints less information comparing to diff.