mjhjmtu

Suppose I want to compare gcc version to see whether the system has the minimum version installed or not.

To check the gcc version, I executed the following

gcc --version | head -n1 | cut -d" " -f4

The output was

4.8.5

So, I wrote a simple if statement to check this version against some other value

if [ "$(gcc --version | head -n1 | cut -d" " -f4)" -lt 5.0.0 ]; then
 echo "Less than 5.0.0"
else
 echo "Greater than 5.0.0"
fi

But it throws an error:

[: integer expression expected: 4.8.5

I understood my mistake that I was using strings to compare and the -lt requires integer. So, is there any other way to compare the versions?

I don't know if it is beautiful, but it is working for every version format I know.

#!/bin/bash
currentver="$(gcc -dumpversion)"
requiredver="5.0.0"
 if [ "$(printf '%sn' "$requiredver" "$currentver" | sort -V | head -n1)" = "$requiredver" ]; then 
 echo "Greater than or equal to 5.0.0"
 else
 echo "Less than 5.0.0"
 fi

(Note: better version by the user 'wildcard': https://unix.stackexchange.com/users/135943/wildcard , removed additional condition)

Here I give a solution for comparing Unix Kernel versions. And it should work for others such as gcc. I only care for the first 2 version number but you can add another layer of logic. It is one liner and I wrote it in multiple line for understanding.

check_linux_version() 
 version_good=$(uname -r 

You can modify this and use it for gcc version checking.

We used to do a lot of version checking in a GNU makefile. We shelled out through the makefile facilities. We had to detect old Binutils and buggy compilers and workaround them on the fly.

The pattern we used was:

#!/usr/bin/env bash

CC=$(command -v gcc)
GREP=$(command -v grep)

# Fixup CC and GREP as needed. It may be needed on AIX, BSDs, and Solaris
if [[ -f "/usr/gnu/bin/grep" ]]; then
 GREP="/usr/gnu/bin/grep"
elif [[ -f "/usr/linux/bin/grep" ]]; then
 GREP="/usr/linux/bin/grep"
elif [[ -f "/usr/xpg4/bin/grep" ]]; then
 GREP="/usr/xpg4/bin/grep"
fi

# Check compiler for GCC 4.8 or later
GCC48_OR_LATER=$("$CXX" -v 2>&1 | "$GREP" -i -c -E "gcc version (4.[8-9]|[5-9].)")
if [[ "$GCC48_OR_LATER" -ne 0 ]];
then
 ...
fi

# Check assembler for GAS 2.19 or later
GAS219_OR_LATER=$("$CXX" -xc -c /dev/null -Wa,-v -o/dev/null 2>&1 | "$GREP" -c -E "GNU assembler version (2.19|2.[2-9]|[3-9])")
if [[ "$GAS219_OR_LATER" -ne 0 ]];
then
 ...
fi