What are $PS1 - 4 in linux

PS1    The value of this parameter is expanded and used as the primary prompt string.  
PS2    The value of this parameter is expanded as with PS1 and used  as
       the secondary prompt string.  The default is ``> ''.
PS3    The value of this parameter is used as the prompt for the select
       command 
PS4    The value of this parameter is expanded  as  with  PS1  and  the
       value  is  printed  before  each command bash displays during an
       execution trace.  The first character of PS4 is replicated  mul-
       tiple  times, as necessary, to indicate multiple levels of indi-
       rection.  The default is ``+ ''.

@Zenonymous

Similar codes

18 votes343 views2 answers
How to delete all branches except master
Shell/Bash
0 vote341 views1 answer
Install brew on raspberry pi
Shell/Bash
0 vote337 views1 answer
Find depth 1
Shell/Bash
4 votes323 views1 answer
Run a command x number of times linux
Shell/Bash
0 vote339 views2 answers
Linux unicode eingeben
Shell/Bash
6 votes323 views2 answers
Redis server stop
Shell/Bash
0 vote339 views4 answers
Calcul en shell
Shell/Bash
1 vote337 views1 answer
Save awk to same file
Shell/Bash
0 vote309 views1 answer
Shell remove consecutive newline
Shell/Bash
19 votes346 views3 answers
Jupyter notebook download for windows 7 64 bit
Shell/Bash