Terminal Tricks 관련

Shell > Article(s)

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Article(s)

• Using Ctrl keys
• Change case
• Run history number
• Run last command
• Run last command and change some parameter using caret substitution
• Run past command that began with
• Bash globbing
• Some handy environment variables
• Using vi-mode in your shell

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Terminal Tricks | Bash-Oneliner

A collection of handy Bash One-Liners and terminal tricks for data processing and Linux system maintenance.

Using Ctrl keys

• Ctrl+a: move to the beginning of line.
• Ctrl+d: if you've type something, Ctrl + d deletes the character under the cursor, else, it escapes the current shell.
• Ctrl+e: move to the end of line.
• Ctrl+k: delete all text from the cursor to the end of line.
• Ctrl+l: equivalent to clear.
• Ctrl+n: same as Down arrow.
• Ctrl+p: same as Up arrow.
• Ctrl+q: to resume output to terminal after Ctrl + s.
• Ctrl+r: begins a backward search through command history.(keep pressing Ctrl + r to move backward)
• Ctrl+s: to stop output to terminal.
• Ctrl+t: transpose the character before the cursor with the one under the cursor, press Esc + t to transposes the two words before the cursor.
• Ctrl+u: cut the line before the cursor; then Ctrl + y paste it
• Ctrl+w: cut the word before the cursor; then Ctrl + y paste it
• Ctrl+x+backspace : delete all text from the beginning of line to the cursor.
• Ctrl+x+Ctrl+e : launch editor defined by $EDITOR to input your command. Useful for multi-line commands.
• Ctrl+z: stop current running process and keep it in background. You can use fg to continue the process in the foreground, or bg to continue the process in the background.
• Ctrl+_: undo typing.

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Change case

• Esc+u: converts text from cursor to the end of the word to uppercase.
• Esc+l: converts text from cursor to the end of the word to lowercase.
• Esc+c: converts letter under the cursor to uppercase, rest of the word to lowercase.

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Run history number

e.g. 53

!53

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Run last command

!!
# run the previous command using sudo
sudo !!

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Run last command and change some parameter using caret substitution

e.g. last command: echo 'aaa' -> rerun as: echo 'bbb'

#last command: echo 'aaa'
^aaa^bbb

#echo 'bbb'
#bbb

#Notice that only the first aaa will be replaced, if you want to replace all 'aaa', use ':&' to repeat it:
^aaa^bbb^:&
#or
!!:gs/aaa/bbb/

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Run past command that began with

e.g. cat filename

!cat
# or
!c
# run cat filename again

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Bash globbing

# '*' serves as a "wild card" for filename expansion.
/etc/pa*wd    #/etc/passwd

# '?' serves as a single-character "wild card" for filename expansion.
/b?n/?at      #/bin/cat

# '[]' serves to match the character from a range.
ls -l [a-z]*   #list all files with alphabet in its filename.

# '{}' can be used to match filenames with more than one patterns
ls *.{sh,py}   #list all .sh and .py files

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Some handy environment variables

$0   :name of shell or shell script.
$1, $2, $3, ... :positional parameters.
$#   :number of positional parameters.
$?   :most recent foreground pipeline exit status.
$-   :current options set for the shell.
$$   :pid of the current shell (not subshell).
$!   :is the PID of the most recent background command.
$_   :last argument of the previously executed command, or the path of the bash script.

$DESKTOP_SESSION     current display manager
$EDITOR   preferred text editor.
$LANG   current language.
$PATH   list of directories to search for executable files (i.e. ready-to-run programs)
$PWD    current directory
$SHELL  current shell
$USER   current username
$HOSTNAME   current hostname

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Using vi-mode in your shell

set -o vi
# change bash shell to vi mode
# then hit the Esc key to change to vi edit mode (when `set -o vi` is set)
k               # in vi edit mode - previous command
j               # in vi edit mode - next command
0               # in vi edit mode - beginning of the command
R               # in vi edit mode - replace current characters of command
2w              # in vi edit mode - next to 2nd word
b               # in vi edit mode - previous word
i               # in vi edit mode - go to insert mode
v               # in vi edit mode - edit current command in vi
man 3 readline  # man page for complete readline mapping