diff --git a/sheets/bash b/sheets/bash
index 06074ea..69253d3 100644
--- a/sheets/bash
+++ b/sheets/bash
@@ -37,9 +37,11 @@ echo ${PIPESTATUS[0]}  # replace 0 with N
 # for loop in one line
 for i in $(seq 1 4); do echo $i; done
 
-# Test if a program exists in the path 
-command -v <program> 2>&1 >/dev/null || error "<program> not installed"
+# Test if a program exists in the path
+# There are false positives: aliases and functions
+command -v ${program} >/dev/null 2>&1 || error "${program} not installed"
 
 # Redirection
-my_command 2>&1 > command-stdout-stderr.txt
-my_command 2>&1 > /dev/null
+# Please note that 2>&1 goes after
+my_command > command-stdout-stderr.txt 2>&1
+my_command > /dev/null 2>&1