Bash / zsh : Using the history expansion

stephane

One of the features of bash I’ve too long overlooked is its history expansion. In this post I’ll show a few examples to get a grip at it.

Recall a previous line

  • Recall the last line 

    kattoo@roadrunner ~ $ date
Sun Mar 28 18:35:12 CEST 2010
kattoo@roadrunner ~ $ !!
date
Sun Mar 28 18:35:13 CEST 2010
kattoo@roadrunner ~ $

  • Recall the n-th last line : 

    kattoo@roadrunner ~ $ echo 1
1
kattoo@roadrunner ~ $ echo 2
2
kattoo@roadrunner ~ $ echo 3
3
kattoo@roadrunner ~ $ !-3
echo 1
1
kattoo@roadrunner ~ $

  • Recall the n-th line of the history 

    kattoo@roadrunner ~ $ history
[…]
533  date
534  date
535  echo 1
536  echo 2
537  echo 3
538  echo 1
539  history
kattoo@roadrunner ~ $ !536
echo 2
2
kattoo@roadrunner ~ $

Re-using previous command line arguments

  • Re-use all the arguments of the previous command 

    kattoo@roadrunner ~ $ touch test-file.txt
kattoo@roadrunner ~ $ scp !* remote:/tmp
scp test-file.txt spaghetti:/tmp
test-file.txt                                             100%    0     0.0KB/s   00:00 
    
kattoo@roadrunner ~ $

  • Re-use the m-th argument from the n-th previous command line 

    kattoo@roadrunner ~ $ echo 1 2 3
1 2 3
kattoo@roadrunner ~ $ echo !-1:2
echo 2
2
kattoo@roadrunner ~ $

  • Re-run the previous command changing occurrences of X by Y 

    kattoo@roadrunner ~ $ echo test
test
kattoo@roadrunner ~ $ ^test^replaced
echo replaced
replaced
kattoo@roadrunner ~ $

That’s about it… those are what I consider to be the most useful history expansion features of bash.

Do you have any other you find especially useful ? Share them in the comments !