Short tricks for long commands
Contributed by: Aditi
- Use
Ctrl+AandCtrl+Eto navigate to the beginning and end of the line respectively. - Hit
Ctrl+Rand enter a word/phrase from a previously used super long command and it will retrieve the last used command with the term.
Reusing previous commands
Contributed by: Aditi
!!is always substituted by the previous command.$ sh /etc/script.sh mv: cannot execute '/etc/script.sh': Permission denied $ sudo !! Script executed.It’s the command equivalent of the upper arrow key!
Bash history
Contributed by: Aditi
To avoid having a command added to your .bash_history file, prefix it with a space i.e. go with ` [command]` instead of [command].
Pausing and running commands
Contributed by: Aditi
Say, you have a terminal text editor open and you’re in the process of editing it. You realize you want to test something out on the terminal.
Instead of closing and re-opening it, you could use Ctrl+Z to pause the application and return to the terminal; followed by the fg command to return to it.
Running commands after logging out of an SSH session
Contributed by: Aditi
This one’s for long commands in an SSH session.
Nohup stands for ‘no hangups’.
Prefixing nohup lets you run time-taking commands in an SSH session after log out too.
So a time-taking script.sh can be run remotely as nohup sh script.sh.
Returning to a previous directory without a pwd
Contributed by: Aditi
Say you accidentally change directories and want to return to the previous directory you were working in.
cd - takes you back to it.
Undoing a commit
Contributed by : Akhil E (akhil-eppa)
Sometimes you may commit the wrong files to the repository and may want to entirely undo a commit. This can be done using the following command
$ git reset --soft ^HEAD~1
Modifying a commit by adding files
Contributed by : Akhil E (akhil-eppa)
Sometimes you may want to add an another file to the existing commit. For that you first add the file to the staging area as follows
$ git add filename
and then commit using the ammend option
$ git commit --amend -m "Added this file"
Syncing forked repository to the original repository
Consributed by : Akhil E (akhil-eppa)
When you fork a repository, the fork contains all the files that were present in the original repository at the time of forking. Now after a certain period if you want to sync the forked repository to the upstream one the following commands have to be executed:
Add remote of original repository in your cloned fork repository as follows
$ git remote add upstream git://github.com/github_handle/repo_name_you_forked_from.git
$ git fetch upstream
Update your fork from original repo to reflect the changes made in original repository
$ git pull upstream master
Finally to reflect these changes in your remote repository from your local repository
$ git push
Stop/Start Displaying Terminal Input
Contributed by: Bhargav SNV
stty -echo
stty echo
When stty -echo is done, input in the terminal won’t be displayed.
When stty echo is done, input in the terminal will be displayed.
Describe Filetype of File or Directory
Contributed by: Bhargav SNV
file [filetype or dirname]
The command describes the type of file/directory provided as a n argument along with a description of its contents.
Create a typescript of terminal session
Contributed by: Bhargav SNV
script [dir/filename]
On executing the command, every command typed after it is logged and added to a typescript with the name filename in the destination described by dir. When we cat filename, the logged commands are executed again. Example:
~$ script script_file
Script started, file is script_file
~$ echo "hi this is in the script"
hi this is in the script
~$echo "hello"
hello
~$ exit
exit
Script done, file is script_file
~$
~$ cat script_file
Script started on 2019-09-14 08:34:06+05:30
~$ echo "hi this is in the script"
hi this is in the script
~$ echo "hello"
hello
# exit
exit
Script done on 2019-09-14 08:35:51+05:30
Here, when we run cat script_file, the commands logged under it are directly executed.
Change command prompt
Contributed by: Bhargav SNV
export PS1="MyPrompt >"
This let’s you edit your prompt text to anything you’d like! Example:
root@ubuntu:~# export PS1="MyPrompt >"
Myprompt >
Running the most recent command starting with a certain character
Contributed by: Akshatha Laxmi
!.
On executing this command, ./a.out runs, if the most recent command starting with . was ./a.out.
Similarly, running !e would run echo hello if the most recent command starting with e was echo hello.
Create a file with date
Contributed by: Akshatha Laxmi
touch filename`date +&d%m%y`
This command creates a file with the date of the day. %d is for the day, %m is for month, %y is for year.
Display certain parts of a text file
Contributed by: Akshatha Laxmi
cat -n filename.txt | sed '11d'
cat -. filename.txt | sed '11!d'
The first command prints everything but line number 11.
The second command prints only line number 11.
Compressing multiple files using gzip
Contributed by: Ramya
cat [file1] [file2] | gzip > [file3.gz]
‘gzip’ command is used to compress/truncate and decompress files. To compress multiple files together you can use the ‘cat’ and ‘gzip’ command with pipe command(lets you use two or more commands such that output of one command serves as the input of the other).This command create a compressed file file3.gz which has contents of both the files.
Checking the success status of a command
Contributed by: Ramya
echo $?
This command is run to check if your previous command was successful or not.It returns 0 on success.
Abbreviating a command
Contributed by: Ramya
alias alias_name='command'
alias command helps to launch any command or group of commands by entering a pre-set string.