BASH - Commands - cat

cat is used to concatenate or write files, text or binary.

Write a file

cat > list.txt

type into the terminal:

aaa
bbb
ccc

Press CTRL+D to stop inputting and save file.

This can only be done at the start of a new line; so <ENTER> needs to be done against the last line before being able to do a CTRL-D.

This would have created the file list.txt.

cat list.txt

returns:

aaa
bbb
ccc

Create another file, named list2.txt, containing:

ddd
eee

cat list.txt list2.txt

returns:

aaa
bbb
ccc
ddd
eee

cat list.txt list2.txt > list3.txt

cat list3.txt

returns:

aaa
bbb
ccc
ddd
eee

cat >> list3.txt

enter:

fff
ggg

Press CTRL+D to stop inputting and save file.

cat list3.txt

returns:

aaa
bbb
ccc
ddd
eee
fff
ggg

cat list.txt - list2.txt > list4.txt

enter:

hhh

Press CTRL+D to stop inputting and save file.

cat list4.txt

returns:

aaa
bbb
ccc
hhh
ddd
eee

NOTE: The hhh data is showing in the middle of the data from the 2 input files.

cat video.001 video.002 video.003 > vid.avi