Boost Your Linux Productivity: 9 Essential Bash Command-Line Tricks

The author shares a collection of Bash command‑line tricks aimed at maximizing efficiency for Linux users, providing ready‑to‑use functions and code snippets that can be added to a .bashrc file.

Technique 1: Add Text to the Top of a File

Use sed to insert a line at the beginning of a file:

sed -i '1s/^/line to insert
/' path/to/file/you/want/to/change.txt

Technique 2: Insert Multiple Lines into a Configuration File

Employ a here‑document to append a block of text:

cat >> path/to/file/append-to.txt <<"EOF"
export PATH=$HOME/jdk1.8.0_31/bin:$PATH
export JAVA_HOME=$HOME/jdk1.8.0_31/
EOF

Technique 3: Recursive Search and Replace Across a Directory

Combine find with sed to replace text in all matching files:

# OSX version
find . -type f -name '*.txt' -exec sed -i '' s/this/that/g {} +

A reusable function added to .bashrc:

function sr {
    find . -type f -exec sed -i '' s/$1/$2/g {} +
}

Usage example:

sr wrong_word correct_word

Technique 4: Open a Temporary File in Vim/Dropbox

Two functions generate a random filename with openssl and open it in GVim:

function sc { gvim ~/Dropbox/$(openssl rand -base64 10 | tr -dc 'a-zA-Z').txt }
function scratch { gvim ~/Dropbox/$(openssl rand -base64 10 | tr -dc 'a-zA-Z').txt }

Technique 5: Download Files with Curl (Follow Redirects, Ignore SSL Errors)

Simple commands for downloading a page or a file:

curl -Lks <some-url>
curl -OLks <some-url-to/a/file.tar.gz>

Technique 6: Bashmarks for Directory Bookmarking

Functions to save, jump to, and list directory bookmarks:

# Save current directory
function s { cat ~/.sdirs | grep -v "export DIR_$1=" > ~/.sdirs1; mv ~/.sdirs1 ~/.sdirs; echo "export DIR_$1=$PWD" >> ~/.sdirs; }
# Jump to bookmark
function g { source ~/.sdirs; cd $(eval echo \$(echo \$DIR_$1)); }
# List bookmarks
function l { source ~/.sdirs; env | grep "^DIR_" | cut -c5- | grep "^.*="; }

Technique 7: Extract a Column from Formatted Output (Awk Example)

Define a reusable function to print a chosen column: function col { awk -v col=$1 '{print $col}'; } Example usage with git status -s:

git status -s | col 2

Technique 8: Skip the First X Words Using a Custom Function

A function that removes the first x fields from input:

function skip { n=$(( $1 + 1 )); cut -d' ' -f$n-; }

Combined with other commands, e.g., to delete Docker images:

docker rmi $(docker images | col 3 | xargs | skip 1)

Technique 9: Create Your Own Command Package

A versatile dur function that supports cloning, moving, tracking branches, copying SSH keys, listing functions, showing definitions, and displaying help:

function dur {
  case $1 in
    cl|clone) git clone [email protected]:nicolapaolucci/$2.git;;
    mv|move) git remote add bitbucket [email protected]:nicolapaolucci/$(basename $(pwd)).git && git push --all bitbucket;;
    tr|trackall) for remote in $(git branch -r | grep -v master); do git checkout --track $remote; done;;
    k|key) ssh $2 "mkdir -p .ssh && cat >> .ssh/authorized_keys" < ~/.ssh/id_rsa.pub;;
    f|fun) typeset -F | col 3 | grep -v _ | xargs | fold -sw 60;;
    d|def) typeset -f $2;;
    h|help|*) echo "[dur]dn shell automation tools"; echo "commands available:"; echo " [cl]one, [mv|move]"; echo " [f]fun lists all bash functions defined in .bashrc"; echo " [def] <fun> shows definition of function defined in .bashrc"; echo " [k]ey <host> copies ssh key to target host"; echo " [tr]ackall, [h]elp";;
  esac
}

Feel free to try these snippets, adapt them to your own .bashrc, and share any improvements.