Command Line History Substitution

Computer History Notes - Herong's Tutorial Notes

∟1978 - The C Shell Developed by Bill Joy

∟Command Line History Substitution

This section provides a quick introduction of C shell command line history substitution.

C Shell Command Line History Substitution: Brings in parts of previously executed commands. History substitution uses the following designators and modifiers:

1. Event Designator - Identifies a previously executed command line:

! - Starts a history substitution.
!! - Identifies the last command line.
!n - Identifies the n'th command line since beginning of the session.
!str - Identifies the previous command line beginning with "str"

2. History Modifier - Modifies the command line identified by the event designator:

:# - Keeps the entire of the identified command line.
:0 - Keeps the first word (the command part) of the identified command line.
:n - The n'th argument of the identified command line.
:$ - The last argument of the identified command line.
:* - The entire argument list of the identified command line.
:h - The head part (path name)of the command and the entire argument list of the identified command line.
:t - The tail part (file name) of the command of the identified command line.

Examples of C shell command line history substitution:

>csh
%who
herong     tty1     Jul 21 21:36
tom        tty2     Jul 21 18:15
%/bin/echo C Shell command line history substitution
C Shell command line history substitution
%touch new file
%ls -l new file
-rw-r--r--   1 herong   users           0 Jul 21 21:56 new file
%history
     1  21:54    who
     2  21:55    /bin/echo C Shell command line history substitution
     3  21:56    touch new file
     4  21:56    ls -l new file
     5  21:58    history
%!!
     1  21:54    who
     2  21:55    /bin/echo C Shell command line history substitution
     3  21:56    touch new file
     4  21:56    ls -l new file
     5  21:58    history
     6  21:59    history
%echo !2:$
echo substitution
substitution
%echo !2:h
echo /bin C Shell command line history substitution
/bin C Shell command line history substitution
%!ls
ls -l new file
-rw-r--r--   1 herong   users           0 Jul 21 21:56 new file