This is a text-only version of the following page on https://raymii.org: --- Title : Bash Bits: Check if a program is installed Author : Remy van Elst Date : 05-05-2019 URL : https://raymii.org/s/snippets/Bash_Bits_Check_if_command_is_available.html Format : Markdown/HTML --- Bash Bits are small examples and tips for Bash Scripts. This bash bit shows you how to check if a piece of software is installed on a machine. It's a function you can use in your shell scripts.

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[All Bash Bits can be found using this link][2] ### command_exists() The function uses the [command][3] binary to check if a binary is available. `command` handles all the magic of searching your path, checking if something is executable, all the dificult stuff that could also be different on other distributions. This is the function: command_exists() { # check if command exists and fail otherwise command -v "$1" >/dev/null 2>&1 if [[ $? -ne 0 ]]; then echo "I require $1 but it's not installed. Abort." exit 1 fi } You can use it in a loop to check multiple binaries: for COMMAND in "awk" "sed" "grep" "tar" "gzip" "which" "openssl" "curl"; do command_exists "${COMMAND}" done If a command does not exist, your script will fail and exit with an error message: I require curl but it's not installed. Abort. [1]: https://www.digitalocean.com/?refcode=7435ae6b8212 [2]: https://raymii.org/s/tags/bash-bits.html [3]: https://manpages.ubuntu.com/manpages/bionic/en/man1/command.1posix.html --- License: All the text on this website is free as in freedom unless stated otherwise. This means you can use it in any way you want, you can copy it, change it the way you like and republish it, as long as you release the (modified) content under the same license to give others the same freedoms you've got and place my name and a link to this site with the article as source. This site uses Google Analytics for statistics and Google Adwords for advertisements. You are tracked and Google knows everything about you. Use an adblocker like ublock-origin if you don't want it. All the code on this website is licensed under the GNU GPL v3 license unless already licensed under a license which does not allows this form of licensing or if another license is stated on that page / in that software: This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . Just to be clear, the information on this website is for meant for educational purposes and you use it at your own risk. I do not take responsibility if you screw something up. Use common sense, do not 'rm -rf /' as root for example. If you have any questions then do not hesitate to contact me. See https://raymii.org/s/static/About.html for details.