{"id":642,"date":"2012-07-10T16:47:51","date_gmt":"2012-07-10T08:47:51","guid":{"rendered":"http:\/\/rmohan.com\/?p=642"},"modified":"2012-07-10T16:47:51","modified_gmt":"2012-07-10T08:47:51","slug":"bash-shortcuts-and-tips","status":"publish","type":"post","link":"https:\/\/mohan.sg\/?p=642","title":{"rendered":"Bash Shortcuts and Tips"},"content":{"rendered":"

Bash Shortcuts and Tips<\/strong><\/h3>\n

Repeating an argument
\n<\/strong>You can repeat the last argument of the previous command in multiple ways. Have a look at this example:<\/p>\n

$ mkdir \/path\/to\/dir
\n$ cd !$<\/p>\n

The second command might look a little strange, but it will just cd to \/path\/to\/dir.<\/p>\n

Some keyboard shortcuts for editing<\/strong><\/p>\n

There are some pretty useful keyboard shortcuts for editing in bash. They might appear familiar to Emacs users:<\/p>\n

\u2022 Ctrl + a => Return to the start of the command you’re typing
\n\u2022 Ctrl + e => Go to the end of the command you’re typing
\n\u2022 Ctrl + u => Cut everything before the cursor to a special clipboard
\n\u2022 Ctrl + k => Cut everything after the cursor to a special clipboard
\n\u2022 Ctrl + y => Paste from the special clipboard that Ctrl + u and Ctrl + k save their data to
\n\u2022 Ctrl + t => Swap the two characters before the cursor (you can actually use this to transport a character from the left to the right, try it!)
\n\u2022 Ctrl + w => Delete the word \/ argument left of the cursor
\n\u2022 Ctrl + l => Clear the screen<\/p>\n

Redirecting both Standard Output and Standard Error:
\n<\/strong>
\n# ls -ltR 2>&1 > \/tmp\/temp.txt<\/p>\n

Specify this in .bashrc<\/strong>
\n<\/em>
\nMake Bash append rather than overwrite the history on disk:<\/p>\n

# shopt -s histappend<\/p>\n

Whenever displaying the prompt, write the previous line to disk:<\/p>\n

# export PROMPT_COMMAND=\u2019history -a\u2019<\/p>\n

To erase duplicate entries in History.<\/p>\n

# export HISTCONTROL=erasedups
\n(or)
\n# export HISTCONTROL=ignoreboth<\/p>\n

To see the history with timestamps<\/p>\n

# export HISTTIMEFORMAT=”%d\/%m\/%Y-%H:%M:%S ”<\/p>\n

To set the Size of the historyHISTSIZE: The number of commands to remember in the command history. The default value is 500.<\/p>\n

# export HISTSIZE=500<\/p>\n

Searching the Past<\/strong>
\n<\/strong><\/strong><\/p>\n